OTHER USES OF SEAWEEDS

9.1 Fertilizers and soil conditioners

There is a long history of coastal people using seaweeds, especially the large brown seaweeds, to fertilize nearby land. Wet seaweed is heavy so it was not usually carried very far inland, although on the west coast of Ireland enthusiasm was such that it was transported several kilometres from the shore. Generally drift seaweed or beach-washed seaweed is collected, although in Scotland farmers sometimes cut Ascophyllum exposed at low tide. In Cornwall (United Kingdom), the practice was to mix the seaweed with sand, let it rot and then dig it in. For over a few hundred kilometres of the coast line around Brittany (France), the beach-cast, brown seaweed is regularly collected by farmers and used on fields up to a kilometre inland. Similar practices can be reported for many countries around the world. For example in a more tropical climate like the Philippines, large quantities of Sargassum have been collected, used wet locally, but also sun dried and transported to other areas. In Puerto Madryn (Argentina), large quantities of green seaweeds are cast ashore every summer and interfere with recreational uses of beaches. Part of this algal mass has been composted and then used in trials for growing tomato plants in various types of soil. In all cases, the addition of the compost increased water holding capacity and plant growth, so composting simultaneously solved environmental pollution problems and produced a useful organic fertilizer.
Seaweed meal is dried, milled seaweed, and again it is usually based on the brown seaweeds because they are the most readily available in large quantities. Species of Ascophyllum, Ecklonia and Fucus are the common ones. They are sold as soil additives and function as both fertilizer and soil conditioner. They have a suitable content of nitrogen and potassium, but are much lower in phosphorus than traditional animal manures and the typical N:P:K ratios in chemical fertilizers. The large amounts of insoluble carbohydrates in brown seaweeds act as soil conditioners (improve aeration and soil structure, especially in clay soils) and have good moisture retention properties. Their effectiveness as fertilizers is also sometimes attributed to the trace elements they contain, but the actual contribution they make is very small compared to normal plant requirements. One company in Ireland that produces milled seaweed for the alginate industry is developing applications for seaweed meal in Mediterranean fruit and vegetable cultivation. "Afrikelp" is another example of a commercially available dried seaweed, sold as a fertilizer and soil conditioner; it is based on the brown seaweed Ecklonia maxima that is washed up on the beaches of the west coast of Africa and Namibia. Weiersbye et al. (no date), in a paper on the Website of the University of Namibia, describe how Ecklonia maxima was tested for potential application as a fertilizer and soil conditioner. For the reader who is interested in more information, this paper illustrates the requirements for a seaweed in these applications
In a chapter about the agricultural uses of seaweeds, Blunden (1991) describes an interesting application of Ascophyllum as a soil conditioner in controlling losses of top soil. Like all brown seaweeds, Ascophyllum contains alginate, a carbohydrate composed of long chains. When calcium is added to alginate, it forms strong gels. By composting the dried, powdered Ascophyllum under controlled conditions for 11-12 days, the alginate chains are broken into smaller chains and these chains still form gels with calcium but they are weaker. The composted product is a dark brown, granular material containing 20-25 percent water and it can be easily stored and used in this form. Steep slopes are difficult to cultivate with conventional equipment and are likely to suffer soil loss by runoff. Spraying such slopes with composted Ascophyllum, clay, fertilizer, seed, mulch and water has given good results, even on bare rock. Plants quickly grow and topsoil forms after a few years. The spray is thixotropic, i.e. it is fluid when a force is applied to spread it but it sets to a weak gel when standing for a time and sticks to the sloping surface. It holds any soil in place and retains enough moisture to allow the seeds to germinate. Composted Ascophyllum has been used after the construction of roads in a number of countries, and has found other uses as well. For more detail see Blunden (1991: 66-68).
Maerl is a fertilizer derived from red seaweeds that grow with a crust of calcium carbonate on the outside, the calcareous red algae, Phymatolithon calcareum and Lithothamnion corallioides. They grow at depths of 1-7 m and are found mainly on the coast of France near the mouths of rivers and calm bays, where the water temperature must be 13°C or higher. They are harvested by dredging or digging and are used to neutralize acid soils, as a substitute for agricultural lime. Maerl is more expensive than lime but is alleged to be better because of the trace elements it contains; however, there may be cheaper ways of adding trace elements.
Seaweed extracts and suspensions have achieved a broader use and market than seaweed and seaweed meal. They are sold in concentrated form, are easy to transport, dilute and apply and act more rapidly. One of the earliest patents was applied for by Plant Productivity Ltd., a British company, in 1949. Today there are several products and brands available, such as Maxicrop (United Kingdom), Goëmill (France), Algifert (Norway), Kelpak 66 (South Africa) and Seasol (Australia).
They are all made from brown seaweeds, although the species varies between countries. Some are made by alkaline extraction of the seaweed and anything that does not dissolve is removed by filtration (e.g. Maxicrop and Seasol). Others are suspensions of very fine particles of seaweed (Goëmill and Kelpak 66).
For Goëmill, the seaweed (Ascophyllum) is rinsed, frozen at -25°C, crushed into very fine particles and homogenized; the result is a creamy product with particles of 6-10 micrometres; everything from the seaweed is in the product. Other chemicals may be added to improve the product for particular applications. Kelpak first appeared in 1983 and the originators say it is made from Ecklonia maxima by a cell-burst procedure that does not involve the use of heat, chemicals or dehydration. Fresh plants are harvested by cutting from the rocks at the stipe (stalk) and then they are progressively reduced in particle size using wet milling equipment. These small particles are finally passed under extremely high pressure into a low-pressure chamber so that they shear and disintegrate, giving a liquid concentrate.
Seaweed extracts have given positive results in many applications. There are probably other applications where they have not made significant improvements, but these receive less, if any, publicity. However, there is no doubt that seaweed extracts are now widely accepted in the horticultural industry. When applied to fruit, vegetable and flower crops, some improvements have included higher yields, increased uptake of soil nutrients, increased resistance to some pests such as red spider mite and aphids, improved seed germination, and more resistance to frost. There have been many, many controlled studies to show the value of using seaweed extracts, with mixed results. For example, they may improve the yield of one cultivar of potato but not another grown under the same conditions. No one is really sure about why they are effective, despite many studies having being made. The trace element content is insufficient to account for the improved yields, etc. It has been shown that most of the extracts contain several types of plant growth regulators such as cytokinins, auxins and betaines, but even here there is no clear evidence that these alone are responsible for the improvements. Blunden (1991) summarizes the situation when he says "there is a sufficient body of information available to show that the use of seaweed extracts is beneficial in certain cases, even though the reasons for the benefits are not fully understood".
Finally there is the question, are seaweed extracts an economically attractive alternative to NPK fertilizers? Perhaps not when used on their own, but when used with NPK fertilizers they improve the effectiveness of the fertilizers, so less can be used, with a lowering of costs. Then there are always those who prefer an "organic" or "natural" fertilizer, especially in horticulture, so seaweed extracts probably have a bright future.
For further details
For useful discussions of most aspects of seaweeds as fertilizers, see Blunden (1991) and Chapman and Chapman (1980). The chapter by Metting et al. (1990) includes van Staden among the authors; he has made many studies on seaweed extracts so the chapter has a stronger emphasis on seaweed extracts, including a useful table summarizing studies that have been made on the effectiveness of seaweed extracts. For a review of the evidence for plant growth regulators in seaweed extracts, and their effectiveness, see Crouch and van Staden (1993).

9.2 Animal feed

For a long time, animals such as sheep, cattle and horses that lived in coastal areas have eaten seaweed, especially in those European countries where large brown seaweeds were washed ashore. Today the availability of seaweed for animals has been increased with the production of seaweed meal: dried seaweed that has been milled to a fine powder. Norway was among the early producers of seaweed meal, using Ascophyllum nodosum, a seaweed that grows in the eulittoral zone so that it can be cut and collected when exposed at low tide. France has used Laminaria digitata, Iceland both Ascophyllum and Laminaria species, and the United Kingdom, Ascophyllum.
Because Ascophyllum is so accessible, it is the main raw material for seaweed meal and most experimental work to measure the effectiveness of seaweed meal has been done on this seaweed. The seaweed used for meal must be freshly cut, as drift seaweed is low in minerals and usually becomes infected with mould. The wet seaweed is passed through hammer mills with progressively smaller screens to reduce it to fine particles. These are passed through a drum dryer starting at 700-800°C and exiting at no more than 70°C. It should have a moisture level of about 15 percent. It is milled and stored in sealed bags because it picks up moisture if exposed to air. It can be stored for about a year.
Analysis shows that it contains useful amounts of minerals (potassium, phosphorus, magnesium, calcium, sodium, chlorine and sulphur), trace elements and vitamins. Trace elements are essential elements needed by humans and other mammals in smaller quantities than iron (approximately 50 mg/kg body weight), and include zinc, cobalt, chromium, molybdenum, nickel, tin, vanadium, fluorine and iodine. Because most of the carbohydrates and proteins are not digestible, the nutritional value of seaweed has traditionally been assumed to be in its contribution of minerals, trace elements and vitamins to the diet of animals. In Norway, it has been assessed as having only 30 percent of the feeding value of grains.
Ascophyllum is a very dark seaweed due to a high content of phenolic compounds. It is likely that the protein is bound to the phenols, giving insoluble compounds that are not attacked by bacteria in the stomach or enzymes in the intestine. Alaria esculenta is another large brown seaweed, but much lighter in colour and in some experimental trials it has been found to be more effective than Ascophyllum meal. It is this lack of protein digestibility that is a distinct drawback to Ascophyllum meal providing a useful energy content. In preparing compound feedstuffs, farmers may be less concerned about the price per kilogram of an additive; the decisive factor is more likely to be the digestibility and nutritive value of the additive.
In feeding trials with poultry, adding Ascophyllum meal had no benefit except to increase the iodine content of the eggs. With pigs, addition of 3 percent Ascophyllum meal had no effect on the meat yield. However, there have been some positive results reported with cattle and sheep. An experiment for 7 years with dairy cows (seven pairs of identical twins) showed an average increase in milk production of 6.8 percent that lead to 13 percent more income. A trial involving two groups each of 900 ewes showed that those fed seaweed meal over a two-year period maintained their weight much better during winter feeding and also gave greater wool production.
The results of trials reported above and in the suggested reading below leave the impression that seaweed meal is probably only really beneficial to sheep and cattle. Certainly the size of the industry has diminished since the late 1960s and early 1970s, when Norway alone was producing about 15 000 tonnes of seaweed meal annually. Nevertheless, a Web search for "seaweed meal" shows that there are companies in at least Australia, Canada, Ireland, Norway, United Kingdom and United States of America advocating the use of seaweed meal as a feed additive for sheep, cattle, horses, poultry, goats, dogs, cats, emus and alpacas. The horse racing industry seems to be especially targeted. One interesting report from a United States of America university states that the immune system of some animals is boosted by feeding a particular Canadian seaweed meal. Obviously the industry is still active, pursuing niche markets and fostering research that might lead back to further expansion.
For further details
Chapman and Chapman (1980) discuss several feeding trials and has tables showing the protein, fat, ash and fibre of some fresh seaweeds and seaweed meal, as well as the vitamin and mineral content of seaweed meal. Indergaard and Minsaas (1991), also have some composition tables, a more detailed description of feeding trials, a discussion on the place of iodine in animal nutrition and the importance of seaweed meal as a source of iodine.

9.3 Fish feed

In fish farming, wet feed usually consists of meat waste and fish waste mixed with dry additives containing extra nutrients, all formed together in a doughy mass. When thrown into the fish ponds or cages it must hold together and not disintegrate or dissolve in the water. A binder is needed, sometimes a technical grade of alginate is used. It has also been used to bind formulated feeds for shrimp and abalone. However, cheaper still is the use of finely ground seaweed meal made from brown seaweeds; the alginate in the seaweed acts as the binder. The binder may be a significant proportion of the price of the feed so seaweed meal is a much better choice. However, since the trend is to move to dry feed rather than wet, this market is not expected to expand.
There is also a market for fresh seaweed as a feed for abalone. In Australia, the brown seaweed Macrocystis pyrifera and the red seaweed Gracilaria edulis have been used. In South Africa, Porphyra is in demand for abalone feed and recommendations have been made for the management of the wild population of the seaweed. Pacific dulse (Palmaria mollis) has been found to be a valuable food for the red abalone, Haliotis rufescens, and development of land-based cultivation has been undertaken with a view to producing commercial quantities of the seaweed. The green seaweed, Ulva lactuca, has been fed to Haliotis tuberculata and H. discus. Feeding trials showed that abalone growth is greatly improved by a high protein content, and this is attained by culturing the seaweed with high levels of ammonia present. Much of the work on seaweeds and abalone has been published in the journals Aquaculture and Journal of Shellfish Research.

9.4 Biomass for fuel

In 1974, the American Gas Association decided to look for a renewable source of methane (natural gas) and sponsored a project to produce seaweed on farms in the ocean, harvest it and convert it to methane by a process of anaerobic fermentation. The project was divided into two parts: one the production and harvesting of the seaweed (biomass), the other the conversion of the biomass to energy (methane, that could be burned to produce energy). The seaweed chosen was the "giant kelp" that grows off the coast of California, Macrocystis pyrifera, because of its high growth rate and ease of harvesting by mechanical means. A test farm was built in the ocean, 8 km off the coast of southern California, and 100 kelp plants, 12-22 m long and taken from natural beds were placed on the farm test structure.
Several storms and the resulting waves and currents caused abrasion of the kelp plants and many were lost. Further studies were made to find better ways of attaching the kelp and to make engineering improvements to the farm structure. However, it was eventually decided to move to smaller-scale, near-shore trials, but the offshore experiments did show that kelp would grow offshore and could utilize the nutrients in deep water upwelling by either natural or artificial means.
The near-shore work concentrated on kelp yield and agronomic practices to improve growth rate and yield and avoided involvement in the engineering of offshore structures. Useful information was gathered in this work, and other types of seaweed were also investigated, such as species of Laminaria, Gracilaria and Sargassum. However, those conducting the other half of the project - biomass conversion to methane by anaerobic fermentation - found that Sargassum gave a poor gas yield. For Macrocystis, the gas yield was good and dependent on the mannitol and alginate content of the seaweed; more gas was produced if the mannitol concentration was high. For Gracilaria, the methane yield related closely to the carbohydrate content, and sometimes the protein content as well.
More work is necessary to find better methods for the conversion step, biomass to methane, on a large scale, although the bench-scale work already done indicates that net energy can result from bioconversion, with good yields of methane. More engineering research is needed for the design of suitable open-ocean structures that will allow the kelp to survive storms and excessive wave movements and currents. Methane from marine biomass is a long-term project and research and development have been scaled down, probably to be revived when a crisis threatens in natural gas supplies.
For further details
A useful summary of the work done from 1974 to about 1990 is given by Flowers and Bird (1990). A much more detailed report of the project is in Bird and Benson (1987). Some parts of a chapter by Morand et al. (1991) that has a particular emphasis on work in Europe, may also be of interest.

9.5 Cosmetics

"Extract of seaweed" is often found on the list of ingredients on cosmetic packages, particularly in face, hand and body creams or lotions. This usually refers to the use of alginate or carrageenan in the product, and their uses in cosmetics have already been discussed in earlier sections. More information on the use of these two hydrocolloids, as well as agar, can be found in the reference suggested below for further reading.
The use of seaweeds themselves in cosmetics, rather than extracts of them, is rather limited.
Milled seaweed, packed in sachets, is sold as an additive to bath water, sometimes with essential oils added. Bath salts with seaweed meal are also sold. Thalassotherapy has come into fashion in recent years, especially in France. Mineral-rich seawater is used in a range of therapies, including hydrotherapy, massage and a variety of marine mud and algae treatments. One of the treatments is to cover a person's body with a paste of fine particles of seaweed, sometimes wrap them in cling wrap, and warm the body with infrared lamps. It is said to be useful in various ways, including relief of rheumatic pain or the removal of cellulite. Paste mixtures are also used in massage creams, with promises to rapidly restore elasticity and suppleness to the skin. The seaweed pastes are made by freeze grinding or crushing. The seaweed is washed, cleaned and then frozen in slabs. The slabs are either pressed against a grinding wheel or crushed, sometimes with additional freezing with liquid nitrogen that makes the frozen material more brittle and easier to grind or crush. The result is a fine green paste of seaweed.
There appears to be no shortage of products with ingredients and claims linked to seaweeds: creams, face masks, shampoos, body gels, bath salts, and even a do-it-yourself body wrap kit. The efficacy of these products must be judged by the user. One company recently pointed out that the lifetime of cosmetic products has reduced over the years and now rarely exceeds three or four years. Perhaps the seaweed products that are really effective will live longer than this.
For further details
An interesting chapter on the uses of seaweeds in cosmetics, especially in Europe, has been written by De Roeck-Holtzhauer (1991). Other information, including some of that in De Roeck-Holtzhauer, can be found on a website constructed by the Department of Botany, University of Cape Town, but more easily accessed via: www.unam.na/henties/research.html (look for "seaweeds and cosmetics"). For those who have access to a database such as the Dow Jones Interactive Publications Library, a search for articles containing "seaweed" with "cosmetics", "harvest", or similar combinations, should reveal the types of products currently available and their claimed benefits.

9.6 Integrated aquaculture

Cultivation of Gracilaria started in Taiwan Province of China in the 1960s as a source of raw material for its agar industry. At first cultivation was on ropes in ditches containing fish pond effluents, but by 1967 it was moved into the fish ponds themselves. This had the twofold benefit of the seaweed using the fish waste material as fertilizer and the fish eating the epiphytes, such as Enteromorpha species, that would otherwise become serious pests for the seaweeds. Control with tilapia (Oreochromis mossambicus) and milkfish (Chanos chanos) was satisfactory as long as the fish were removed before they started to eat the Gracilaria; larger fish were periodically removed and replaced by small fish.
This concept of polyculture, or integrated aquaculture to use the more recent terminology, has since been utilized in many situations where the effluent from the aquaculture of one species, potentially threatening environmental damage, can be utilized by another species to its advantage, with a reduction in pollution.
Various strategies have been tried. Seaweed cultivation around the outside of fish cages has led to significantly better growth of seaweed but was only partly successful in removing the large amount of nutrients coming from the fish cages (Figure 63). Unattached Gracilaria has been grown in the effluent from shrimp ponds (Figure 64).
Semi-enclosed or land-based systems have been suggested, but the higher capital investment has been a deterrent. In Israel, an integrated system has been tried. Here the effluent from Japanese abalone culture tanks drained into a fish tank that used pellet feeding. The fish effluent in turn drained into a seaweed cultivation tank (species of Ulva); the seaweed produced was used to feed the abalone. The abalone and fish grew well, a surplus of seaweed was produced and the ammonia nitrogen in the seaweed effluent was reduced to 10 percent of the total amount fed to the system.
In Hawaii, where Gracilaria species are eaten as fresh salad vegetables, shrimp farm effluent has been used to fertilize Gracilaria in floating cage culture. In Brazil, cage aquaculture of shrimp in the open sea has been studied in an attempt to reduce the environmental impact of the shrimp industry. It was found that culturing seaweed inside the shrimp cages can improve the economic result for both shrimp and seaweed. In Chile, when Gracilaria seaweed cultivation was integrated with salmon farms the seaweed grew well and removed a large amount of the ammonium excreted by the fish. In France, trials were run with Gracilaria growing in closed and semi-enclosed systems, in the effluents from oyster farms; 90 percent efficiency was recorded in removal of ammonia coupled with useful growth of the seaweed. Porphyra species are the source of the human food, nori, and so their use in integrated aquaculture is an attractive economic alternative, particularly because they are very efficient in taking up nutrients. Trials are being run on the east coast of Canada and United States of America to combine Porphyra with salmon farming.
These are just a few examples of the small- and large-scale uses that are evolving in the integrated aquaculture of seaweeds with other species. Integrated aquaculture is developing as solutions are sought to problems of environmental sustainability, including the management of coastal areas and the disposal of effluents from large-scale aquaculture activities.

FIGURE 63
Gracilaria growing in fish cages (Songkhla Lagoon, Thailand).

FIGURE 64
Unattached Gracilaria growing in effluent drains from shrimp ponds (southern Thailand).

For further details
Troell et al. (1999) is especially recommended for an introduction to the topic. The references that follow elaborate on some of the examples given above, and in their introductions may provide the reader with other general background information and further references: Troell et al. (1999), Neori, Shpigel and Ben-Ezra (2000), Nelson et al. (2001), Lombardi, Marques and Barreto (2001), Buschmann, Troell and Kautsky (2001) and Chopin et al. (1999)

9.7 Wastewater treatment

There are two main areas where seaweeds have the potential for use in wastewater treatment. The first is the treatment of sewage and some agricultural wastes to reduce the total nitrogen- and phosphorus-containing compounds before release of these treated waters into rivers or oceans. The second is for the removal of toxic metals from industrial wastewater.

9.7.1 Treatment of wastewater to reduce nitrogen- and phosphorus-containing compounds

Eutrophication is the enrichment of waters with nutrients such as minerals and nitrogen- and phosphorus-containing materials. This frequently leads to unwanted and excessive growth of aquatic or marine plants; blooms of blue-green algae are an example, unfortunately becoming more common. Eutrophication can occur naturally, but it can be accelerated by allowing water, rich in dissolved fertilizers, to seep into nearby lakes and streams, or by the introduction of sewage effluent into rivers and coastal waters.
Seaweeds can be used to reduce the nitrogen and phosphorus content of effluents from sewage treatments. Many seaweeds have a preference to take up ammonium as the form of nitrogen for their growth and ammonium is the prevalent form of nitrogen in most domestic and agricultural wastewater. Another important feature of many seaweeds is their ability to take up more phosphorus than they require for maximum growth. It would be preferable to use seaweeds that have some commercial value, but these do not necessarily have the ability to withstand the conditions encountered in the processing of the wastewater. There is a need for the seaweed to be able to tolerate a wide variation in salinity because of the dilution of salinity by the sewage or wastewater. Intertidal and estuarine species are the most tolerant, especially green seaweeds such as species of Enteromorpha and Monostroma. Of the red and brown seaweeds that are of interest because of their commercial value, tropical or subtropical forms have been successfully used, while cold-temperate species are usually too sensitive to changing seasons and may fail to grow (and remove nutrients) in the winter months. While many investigations have demonstrated the suitability of seaweeds for wastewater treatments, their use on a large scale is yet to be implemented, although this may change with the increasing realization of the need to protect marine environments.
For further details
A good discussion of this topic can be found in Schramm (1991b), which includes a table showing the seaweeds that have been tested or used for wastewater treatment, together with references to the original publications.

9.7.2 Removal of toxic metals from industrial wastewater

The accumulation of heavy metals (such as copper, nickel, lead, zinc and cadmium) by seaweeds became apparent when those seaweeds used as human foods were first analysed. The heavy metal content, especially of the large brown seaweeds, varied according to their geographic source and sometimes to their proximity to industrial waste outlets. From these studies came the idea of using seaweeds as biological indicators of heavy metal pollution, either from natural sources or from activities such as mining or disposal of industrial wastes. This has been successfully implemented using brown seaweeds such as Sargassum, Laminaria and Ecklonia, and the green seaweeds Ulva and Enteromorpha.
A further extension of this ability of some seaweeds to take up heavy metals is to use them to remove heavy metals in cleaning up wastewater. While there have been many small-scale trials, it is difficult to find reports of actual implementation on a large scale. Milled, dried species of the brown seaweeds Ecklonia, Macrocystis and Laminaria were able to adsorb copper, zinc and cadmium ions from solution. In another laboratory-scale trial, Ecklonia maxima, Lessonia flavicans and Durvillaea potatorum adsorbed copper, nickel, lead, zinc and cadmium ions, though to varying extents depending on the seaweed type and metal ion concentration. After the extraction of alginate from brown seaweeds there is an insoluble waste product, mostly cellulose, and the adsorbing properties of this have been tested and found to equal some of the brown seaweeds. Using such a waste material is obviously more attractive than use of the dried seaweed itself. Another waste product, from the production of Kelpak, the liquid fertilizer previously mentioned, has also been tested and found to adsorb copper, cadmium and zinc just as effectively as the seaweed from which it is derived. So there is the potential to use either seaweed or residues remaining from seaweed extraction. It is a matter of whether this is the most economical way to do so, depending on their availability and cost at the source of the wastewater.
For further details
A recent review by Pan, Lin and Ma (2000) is a useful starting point. For some examples of trials using seaweeds and seaweed residues, see Valdam and Leite (2000), Stirk and van Staden (2000), Aderhold, Williams and Edyvean (1996) and Figueira et al. (2000). In this last reference, look in the Introduction for earlier papers published by B. Volesky as these illustrate the type of investigations that have been made in this topic over the past decade.

SEAWEEDS USED AS HUMAN FOOD

8.1 Introduction

For several centuries there has been a traditional use of seaweeds as food in China, Japan and the Republic of Korea. As people from these countries have migrated around the world, this custom has moved with them, so that today there are many more countries where the consumption of seaweed is not unusual. Coastal dwellers in tropical climates such as Indonesia and Malaysia have also eaten fresh seaweeds, especially as salad components.
In recent years there has been a strong movement in France to introduce seaweed into the European cuisine, with some success, although it is still regarded as an exotic component of the menu. It has gained more acceptance in regions like California and Hawaii, where communities of Japanese are larger and the taste for seaweeds spreads out into the surrounding population through finding them on restaurant menus and supermarket shelves.
On the east coast of United States of America and Canada, around Maine, New Brunswick and Nova Scotia, some companies have begun cultivating seaweeds onshore, in tanks, specifically for human consumption, and their markets are growing, both in those two countries and with exports to Japan. Ireland and Northern Ireland are showing a renewed interest in seaweeds that were once a traditional part of the diet. Already on the market in many countries around the world are cooking books incorporating recipes using "sea vegetables". With the current trend for consumers to embrace organically grown foods and "natural" foods from clean environments, seaweeds should receive an increasing acceptance.

8.2 Nori or purple laver (Porphyra spp.)

This is the purplish-black seaweed often seen wrapped around a small handful of rice in sushi. It comes largely from cultivation in Japan, the Republic of Korea and China. In Japan's list of products from marine culture, nori has the highest production, followed by oysters, yellowtails and wakame, the last being another seaweed used as food.
Nori grows as a very thin, flat, reddish blade (Figure 47), and is found in most temperate intertidal zones around the world, illustrated by its history of being eaten by the indigenous peoples of northwest America and Canada, Hawaii, New Zealand and parts of the British Isles.

FIGURE 47
Porphyra umbilicalis. Scale: width of specimen is about 20 cm

J.M. JONES

FIGURE 48
Net cultivation of Porphyra

R.J. KING

It is among the most nutritious seaweeds, with a protein content of 30-50 percent, and about 75 percent of that is digestible. Sugars are low (0.1 percent), and the vitamin content very high, with significant amounts of Vitamins A, C, niacin and folic acid, but the shelf life of vitamin C can be short in the dried product. During processing to produce the familiar sheets of nori, most salt is washed away, so the sodium content is low. The characteristic taste of nori is caused by the large amounts of three amino acids: alanine, glutamic acid and glycine.
While Porphyra can be collected by hand from natural sources, most is now derived from cultivation. Porphyra has an unusual life cycle that was not understood until the early 1950s. Until then it had been cultivated but nobody knew where the spores came from, so there was little control over the whole cultivation process.
The seaweed, as we know it, sheds spores and these settle on mollusc shells: in nature it is any nearby; in cultivation they are deliberately placed beneath the blades of the seaweed. An alternate generation of filamentous algae develops from these spores and burrow into the surface of the shell; this is called the conchocelis stage. With lowered light (shorter days) and lower temperatures, more, but different, spores form from the filaments and these are allowed to settle onto nets. It is these spores that develop into the blades of Porphyra. The nets are placed in the ocean in such a way that they are exposed to air for a few hours a day (Figure 48). The Porphyra is reasonably resistant to some drying out, but the pest seaweeds that try also to grow on the nets do not survive. The nets were originally set up in intertidal flat areas, but as space became short, a new system of floating nets in deeper water was devised. The spores germinate on the nets and grow into new blades of Porphyra.
For more information about the life cycle of Porphyra and the methods used to seed nets and manipulate them in the sea, descriptions with useful illustrations can be found in Oohusa (1993), Kain (1991) or Mumford and Muira (1988). For information on its nutritive value, see Nisizawa (1987) or Chapman and Chapman (1980: 108-109). For a review of the nutritional value of proteins in nori and other edible seaweeds, see Fleurence (1999).
Good quality nori is in demand in the Republic of Korea, where production methods differ between the northern and southern areas. The floating system is used in the south and production costs are cheaper than in the north, where the original shallow-water pole system is used. However, the northern quality is better and it commands a higher price.
Attempts have been made to cultivate Porphyra in non-Asian countries, notably the west and east coasts of United States of America. Cultivation on the west coast - Puget Sound in Washington State - was successful but became unviable commercially when residents of the shore areas objected to the presence of seaweed farms and access to sufficient space to expand the pilot farm was refused. In Maine, on the east coast, cultivation problems with indigenous species of Porphyra slowed progress, but as these were being overcome, regulatory issues between landholders and commercial fishermen again delayed progress. In the meantime, the company was reorganized, decided to develop other marine biotechnology interests and to discontinue the nori project.

FIGURE 49
Distribution and marketing chain for seaweeds in Japan (after Pacific Islands Centre, Tokyo).

Japanese cultivation of Porphyra yields about 400 000 wet tonne/year and this is processed into ca 10 billion nori sheets (each 20×20 cm, 3.5-4.0 g), representing an annual income of US$ 1 500 million. In the Republic of Korea, cultivation produces 270 000 wet tonnes, while China produces 210 000 wet tonnes.
Processing of wet Porphyra into dried sheets of nori has become highly mechanized, rather like an adaptation of the paper-making process. The wet Porphyra is rinsed, chopped into small pieces and stirred in a slurry. It is then poured onto mats or frames, most of the water drains away, and the mats run through a dryer. Rate of drying is carefully controlled by adjusting conveyer speed and temperature. The sheets are peeled from the mats and packed in bundles of ten for sale. This product is called hoshi-nori, which distinguishes it from yaki-nori, which is toasted. Toasted nori is nori pre-toasted and sold in sealed packages; in use it may be brushed with a mixture of soy sauce, sugar, sake and seasonings.
Nori is used mainly as a luxury food. It is often wrapped around the rice ball of sushi, a typical Japanese food consisting of a small handful of boiled rice with a slice of raw fish on the top. After a short baking (slight toasting or baking brings out the flavour), nori can be cut into small pieces and sprinkled over boiled rice or noodles. It can be incorporated into soy sauce and boiled down to give an appetising luxury sauce. It is also used as a raw material for jam and wine. In China it is mostly used in soups and for seasoning fried foods. In the Republic of Korea it has similar uses to Japan, except that a popular snack with beer is hoshi-nori that has been quickly fried in a pan with a little oil.
The distribution and marketing chain for nori and other Japanese seaweeds is illustrated in Figure 49. Dried nori is in constant oversupply in Japan and producers and dealers are trying to encourage its use in United States of America and other countries. Production and markets in China are expanding, although the quality of the product is not always as good as that from the Republic of Korea and Japan. Good quality nori is in demand in the Republic of Korea.

8.3 Aonori or green laver (Monostroma spp. and Enteromorpha spp.)

These two green seaweed genera are now cultivated in Japan. Enteromorpha cultivation has also been attempted in the Republic of Korea but with limited success.
Monostroma latissimum occurs naturally in the bays and gulfs of southern areas of Japan, usually in the upper eulittoral zone. It is cultivated in shallow, calm waters, such as are found in bays and estuaries, but, like Porphyra, it can also be grown in deeper waters using floating rafts. It is a flat, leafy plant and only one cell thick. It averages 20 percent protein and has a useful vitamin and mineral content. It has a life cycle involving an alternation of generations (see Section 1.5), one generation being the familiar leafy plant, the other microscopic and approximately spherical. It is this latter generation that releases spores that germinate into the leafy plant.
For cultivation, these spores are collected on rope nets by submerging the nets in areas where natural Monostroma populations grow; the spores settle on the nets as they are released by the microscopic spheres. There are other artificial ways of seeding the nets that are used if the waters around the natural populations are too muddy. The seeded nets are then placed in the bay or estuary using either of the two methods previously described for Porphyra, fixed to poles so that they are under water at high tide and exposed for about four hours at low tide, or using floating rafts in deeper water. The nets are harvested every 3-4 weeks (for the method, see below for Enteromorpha) and the growing season allows about three to four harvests. The harvested seaweed is washed well in seawater and freshwater. It can then either be processed into sheets and dried, as described for Porphyra, for sale in shops, or dried, either outside or in dryers, and then boiled with sugar, soy sauce and other ingredients to make "nori-jam".
Enteromorpha prolifera and Enteromorpha intestinalis (Figure 50) are both cultivated, although the production of Monostroma is much greater. Both species are found in bays and river mouths around Japan, and are also found in many other parts of the world, including Europe and North America. It can thrive in both salt and brackish waters and is usually found at the top of the sublittoral zone. It contains about 20 percent protein, little fat, low sodium and high iron and calcium. Its vitamin B-group content is generally higher than most vegetables, and while its vitamin A is high, it is only half of that found in spinach. It was and is collected from natural sources, but careful cultivation can ensure greater uniformity and better colour (green is good, greener is better). Again the life history involves an alternation of generations, but this time both generations have the same appearance of long, tubular filaments.

FIGURE 50
Enteromorpha intestinalis (Specimen from National Herbarium, Royal Botanic Gardens, Sydney. Collector: S. Skinner).

For cultivation, rope nets are seeded with spores by submerging them in areas where Enteromorpha is growing naturally, usually attached to rocks; the better areas have calm waters and sandy bottoms. In the Republic of Korea, seed collection is from June to August and the strings or ropes are taken to culture sites in September; in Japan, seeding is done in September, and by early November young plants are visible. The nets are placed in calm bays or estuaries using either fixed poles in shallow waters or floating rafts in deeper waters.
Harvesting can be done 2-3 times during the growing period, either by hand picking from the nets or by machine. As with Porphyra and Monostroma, the nets are dragged out of the water and over a cylinder equipped with cutters, mounted in a boat, and then fed back into the water. This is well illustrated in Figure 17A in Ohno and Largo (1998). Hand picking yields the best product, but is slow in comparison with machine harvesting. The harvested seaweed is washed in freshwater and dried in large trays. It can be lightly toasted to improve the flavour, and powdered for use as a condiment on soups and foods, or it can be crushed into small pieces and used as a garnish.
"Sea lettuce" adequately describes a thin green seaweed, a species of Ulva, that appears in the mid to lower eulittoral zone. It is collected from the wild and sometimes added to the above two seaweeds as part of aonori. It has a higher protein content than the other two, but much lower vitamin content, except for niacin, which is double that of Enteromorpha.
For further details
For the life cycles of Monostroma and Enteromorpha, and the methods used to seed nets and manipulate them in the sea, descriptions with useful illustrations can be found in Ohno (1993) and there is also some information in Kain (1991).
For data on their nutritive values and those of Ulva, see Nisizawa (1987).

8.4 Kombu or haidai (Laminaria japonica)

Kombu is the Japanese name for the dried seaweed that is derived from a mixture of Laminaria species. These include L. longissima, L. japonica, L. angustata, L. coriacea and L. ochotensis. These are all harvested from natural sources, mainly on the northern island of Hokkaido, with about 10 percent coming from the northern shores of Honshu. The first three of the above are the main components of the harvest. The plants grow on rocks and reefs in the sublittoral zone, from 2-15 m deep. They prefer calm water at temperatures between 3° and 20°C.
Haidai is the Chinese name for Laminaria japonica, a seaweed that was introduced to China accidentally from Japan in the late 1920s. Previously, China had imported all requirements from Japan and the Republic of Korea. It is now cultivated on a large scale in China. It is a large seaweed, usually 2-5 m long, but it can grow up to 10 m in favourable conditions (Figure 51). It requires water temperatures below 20°C. Laminaria japonica grows naturally in the Republic of Korea and is also cultivated, but on a much smaller scale; the demand is lower because Koreans prefer wakame (Undaria pinnatifida).
Laminaria species contain about 10 percent protein, 2 percent fat and useful amounts of minerals and vitamins, though generally lower than those found in nori. For example, it has one-tenth the amounts of vitamins and niacin, half the amount of B1 but three times the amount of iron compared with nori. Brown seaweeds also contain iodine, which is lacking in nori and other red seaweeds.

FIGURE 51
Fresh Laminaria japonica (longer piece on right) and Undaria pinnatifida.

Japan has a tradition of eating kombu, going back for several centuries, and had a plentiful supply of Laminaria by harvesting from its natural beds on Hokkaido. The naturally growing plants are biennial and are ready for harvesting after 20 months. Harvesting is from June to October, from boats. Hooks of various types are attached to long poles and used to twist and break the seaweed from the rocky bottom. As demand grew in the 1960s, attempts were made to develop artificial cultivation methods, but the two-year cycle meant the costs were too high. In the 1970s, forced cultivation was introduced, reducing the cultivation period to one year, similar to the system developed in China in the early 1950s. Today, about one-third of Japan's requirements come from cultivation, with the remaining two-thirds still coming from natural resources.
China had no natural sources of Laminaria but it appeared in the northern city of Dalian in 1927 with the importation of logs from Hokkaido in Japan. The Japanese, who then occupied that part of China, tried to increase the growth by their traditional method of throwing rocks into the sea. As it spread, it was harvested from these sublittoral rocks, but there had always been a strong demand for haidai in China, so importation was still necessary. In the 1950s, China developed revolutionary techniques for its cultivation and today about 4 million tonnes of wet seaweed are harvested annually.
For cultivation, Laminaria must go through its life cycle, and this involves an alternation of generations. The seaweed itself is the so-called sporophyte stage of the cycle. The spores that it sheds cannot survive above 20°C and the system developed in China overcame this problem by ensuring the spores are shed in seawater that has been cooled below 20°C. In early summer, mature seaweed is dried out slightly and plunged into cooled seawater in tanks. The drying out helps to induce the liberation of the spores. Prior to this, string is wound around frames and placed in the tank of cooled seawater so that when the spores are released, they settle on the string. The frames are then moved into shallow (20-30 cm deep) tanks in a glasshouse and kept in water at 8-10°C that is enriched with nitrogen and phosphate fertilizers. The spores on the string then develop into microscopic gametophytes, which is the alternate generation. The gametophytes mature on the string and after a few weeks they release eggs and spermatozoids that fuse together, and from this a new sporophyte grows. In one to two months, the string becomes crowded with young sporophytes (sporelings) 1-2 mm high. When the sea temperature has fallen below 20°C, the sporelings on the strings are placed in the sea for 1-2 months, until they grow to 10-15 cm.
By now it is November, and the young sporelings are removed from the string and placed individually in the lay of a rope; the rope is untwisted a little, the sporeling placed between the cords and then the rope is allowed to resume its normal twist. The ropes with the young sporophytes are attached to floating rafts. There are two basic types of these rafts.
The first type is the single-rope or hanging-kelp rope raft, which uses a large diameter rope about 60 m long that is kept floating using glass or plastic buoys fixed every 2-3 m. Each end of the rope is anchored to a wooden peg driven into the sea bottom. Hanging down from this rope at 50 cm intervals are the ropes with the young sporophytes attached. Each rope is from 1 to 2 m long and with a bag of stones on the end to weigh it down (Figure 52a). The floating ropes are laid out in the sea about 10 m apart, to allow the passage of a small boat between the ropes.
The second type of raft is the double-raft or horizontal-line raft (Figure 52b). Here three long ropes with floats attached are laid out parallel, about 5 m apart. The short ropes holding the young sporophytes are tied across two ropes so that the sporophyte ropes are more or less horizontal (Figure 53). This arrangement means each sporophyte has about equal access to light, whereas with the vertical lines, the plants on the deeper end get less light and do not grow as well as those at the top end, a problem that can be overcome by reversing the rope halfway through the growing season.
The horizontal-line raft is more resistant to water movement and therefore has less access to nutrients. Generally, the single-rope raft method is better, especially in clear water, and it has the advantage that the depth at which the plant is growing can be easily adjusted. If the water is turbid, the double raft method is used.

FIGURE 52A
Hanging-kelp raft (after Tseng 1987).

FIGURE 52B
Horizontal-line raft (after Tseng 1987).

FIGURE 53
Horizontal-line raft with Laminaria japonica (Yanti, China).

FIGURE 54
Harvested Laminaria japonica. The rope (on left-hand edge of the seaweed) holding the seaweed was removed from between the two floating ropes in Figure 53.

In China, the largest region for Laminaria cultivation is in the Yellow Sea, which has been found to be low in nitrogen fertilizer. Yields are increased when the floating raft areas, which are usually set out in rectangles, are sprayed with a nitrate solution using a powerful pump mounted in a boat. The plants take up the nitrate quickly and very little is lost in the sea. In Japan, the cultivation is mainly in the waters between Honshu and Hokkaido islands and fertilizing is not necessary. Harvesting is done from mid-June to early July. The kelp ropes are detached from the floating ropes and collected in small boats (Figure 54), many of which are towed in line by a motor boat. The kelp is usually laid out in the sun to dry (Figure 55), and then packed into bales.
In Japan, the whole seaweed is washed thoroughly with seawater, cut into 1 m lengths, folded and dried; the product is suboshi kombu and is delivered to the local fisheries cooperative. From there it follows the type of marketing chain previously shown in Figure 49.
In China, haidai is regarded as a health vegetable because of its mineral and vitamin content, especially in the north, where green vegetables are scare in winter. It is usually cooked in soups with other ingredients. In Japan, it is used in everyday food, such as a seasoned and cooked kombu that is served with herring or sliced salmon. Suboshi kombu can be treated by placing it in a boiling solution of a dye, malachite green, to give it a dark green colour, after which it is partly dried and then shredded with a plane; this is aokombu or green kombu. Kombu tea is like green kombu but shaved a second time so the shavings are like tea leaves. Other variations are used to produce different kombu types. In cooking, green kombu is boiled with meat, fish and soups. Powdered kombu is added to sauces and soups, and to rice. Green kombu and tea kombu are used to make a tea-like beverage.

FIGURE 55
Drying Laminaria japonica (Yanti, China).

For further details

• For more information on the nutrients in Laminaria, see Nisizawa (1987) and Nisizawa et al. (1987).
  
• For more details of Laminaria cultivation, see Tseng (1987), Kain (1991), and Kawashima (1993).
  
• For more about different types of kombu and ways of cooking them, see Chapman and Chapman (1980: 76-78) and Nisizawa (1987).

8.5 Wakame, quandai-cai (Undaria pinnatifida)

Undaria pinnatifida, a brown seaweed (Figures 51 and 56), occurs on rocky shores and bays in the temperate zones of Japan, the Republic of Korea and China. It grows on rocks and reefs in the sublittoral zone, down to about 7 m. It grows best between 5° and 15°C, and stops growing if the water temperature rises above 25°C. It has been spread, probably via ship ballast water, to France, New Zealand and Australia.
Wakame has a high total dietary fibre content, higher than nori or kombu. Like the other brown seaweeds, the fat content is quite low. Air-dried wakame has a similar vitamin content to the wet seaweed and is relatively rich in the vitamin B group, especially niacin; however, processed wakame products lose most of their vitamins. Raw wakame contains appreciable amounts of essential trace elements such as manganese, copper, cobalt, iron, nickel and zinc, similar to kombu and hiziki.
Undaria is an annual plant with a life cycle similar to Laminaria. It has an alternation of generations with the large seaweed as the sporophyte and a microscopic gametophyte as the alternate generation. Some wild material is collected and used locally, but all the commercial products are from cultivated plants. Cultivation methods are very similar to those used for Laminaria, although some of the temperature tolerances are different. The Republic of Korea is the largest producer of wakame. There, seeding starts in April; string is wound around frames and these are immersed in tanks. Fresh, mature plants (sporophytes) are air-dried in the shade for about an hour and then immersed in the tanks so spores are released and settle on the strings. The tanks are exposed to natural light and the seawater in the tanks is changed monthly; the water temperature must be kept below 25°C or the gametophytes may die. The gametophytes mature, fertilized eggs form on the strings and develop into young sporophytes. During September-October the sea water drops below 23°C and the frames or strings are moved to protected intermediate culture areas so that the young plants can adapt to open seawater conditions.

FIGURE 56
Undaria pinnatifida, dried specimen (China).

Once the young plants are 1-2 cm long, the strings are removed from the frames and wound around a rope that is suspended by floats and anchored to the bottom at each end. However, a variation from the Laminaria cultivation is that the rope long-lines are suspended 2-3 m below the surface. In sheltered bays, the ropes are placed 10 m apart; in open waters, where there is more movement, the single ropes are assembled into a grid pattern using connecting ropes to hold the long-lines about 2 m apart. Harvesting is in two stages. First the plants are thinned out by cutting them off at a point close to the rope. This is done by pulling the rope over the edge of a boat, cutting and dragging the plant into the boat. The remaining plants on the rope have plenty of space and continue to grow. Harvesting finishes in April. In Japan, the seeded strings are often cut into small lengths and inserted in the twist of a rope that is then hung vertically from a floating rope, much the same as is done with Laminaria. Harvesting in southern Japan is from March to May, but around Hokkaido it is from May to July.
Cultivation has also been undertaken in France. Here the above methods were found to be inappropriate because the high nutrient concentrations in the water allowed a large variety of other plant and animal life (epiphytes) to grow on the frames holding the strings. The constant cleaning of the frames proved to be too expensive. Instead, the alternate generation, the gametophytes, are formed and maintained in a sterile laboratory medium. One month before out-planting the gametophytes are brought to maturation. After fertilized eggs (zygotes) are formed, the solution with the suspended zygotes is sprayed onto a nylon line that is wound around a frame. The zygotes germinate and young sporophytes begin to grow on the frames, which are free of epiphytes. The sporophytes are out-planted on floating ropes in the usual way.
After harvesting, the plants are washed with seawater, then freshwater, the central midrib is removed and the pieces are dried in the sun or a hot air dryer; this is suboshi wakame. However, this product often fades during storage because various enzymes are still active. To overcome this, another process can be used in which the fresh seaweed is mixed with ash from wood or straw, spread on the ground for 2-3 days, then placed in a plastic bag in the dark. The alkalinity of the ash inactivates the enzymes. The plants are washed with seawater, then freshwater to remove the salt and ash, the midrib is removed and the pieces are dried. This is haiboshi wakame and it keeps its deep green colour for a long time.
Blanched and salted wakame is the major wakame product. Fresh wakame is plunged into water at 80°C for 1 minute and cooled quickly in cold water. About 30 kg of salt per 100 kg of seaweed are mixed and stored for 24 hours. This dehydrates the wakame; excess water is removed and the seaweed stored at -10°C. When ready for packaging, it is taken from storage, the midribs are removed and the pieces placed in plastic bags for sale. It is a fresh green colour and can be preserved for long periods when stored at low temperatures.
Cut wakame is a very convenient form, used for various instant foods such as noodles and soups. It is one of the most popular dried wakame products. It is made from blanched and salted wakame which is washed with freshwater to remove salt, cut into small pieces, dried in a flow-through dryer and passed through sieves to sort the different sized pieces. It has a long storage life and is a fresh green colour when rehydrated.
In the Republic of Korea, wakame is enjoyed as an ingredient in soybean and other soups, as well as vinegared seaweed salads. In recent times there has been an overproduction of wakame and this has led to increased marketing efforts through the introduction of new products, such as seaweed salad, pre-cooked wakame, powdered wakame for use as a condiment and further expansion of the uses of cut, dried wakame.
Wakame is more popular in the Republic of Korea than in Japan, although the market in Japan has expanded. Wakame is traditionally regarded as a luxury food in both countries, although overproduction has led to reduced prices in recent times. The Republic of Korea produces ten times more Undaria than Laminaria; it produces four times more Undaria than Japan. Production in China has apparently increased, as has its exports to Japan. In 2001, the Chinese seaweed industry agreed to reduce exports of wakame to Japan, beginning in April 2002. Japanese wakame producers agreed to support Chinese seaweed growers in finding other overseas markets and expanding demand in China. Japan imported 180 000 tonnes of wakame from China from mid-1999 to mid-2000, a 2.4-fold increase from four years earlier. Production in Japan halved during that one year period.
For further details
For further detail on the nutrients in Undaria, see Nisizawa (1987) and Nisizawa et al. (1987).
For more information about the cultivation of Undaria in the Republic of Korea, see Sohn and Kain (1989), Kain (1991) and Sohn (1998). For cultivation in Japan, see Ohno and Matsuoka (1993).
For details of the cultivation method used in France see Kaas (1998).
Methods of processing raw Undaria into marketable products are discussed in Nisizawa et al. (1987) and Yamanaka and Akiyama (1993).

8.6 Hiziki (Hizikia fusiforme)

Hizikia fusiforme is a brown seaweed with a finer frond (leaf) structure (Figure 57) than wakame and kombu. It is collected from the wild in Japan and cultivated in the Republic of Korea, grows at the bottom of the eulittoral and top of the sublittoral zones, and is on the southern shore of Hokkaido, all around Honshu, on the Korean peninsula and most coasts of the China Sea. About 90 percent of the Republic of Korea production is processed and exported to Japan.
The protein, fat, carbohydrate and vitamin contents are similar to those found in kombu, although most of the vitamins are destroyed in the processing of the raw seaweed. The iron, copper and manganese contents are relatively high, certainly higher than in kombu. Like most brown seaweeds, its fat content is low (1.5 percent) but 20-25 percent of the fatty acid is eicosapentaenoic acid (EPA).
Some is collected from the wild, but this has decreased as cultivation has grown. For example, in 1990 in the Republic of Korea, 10 000 wet tonnes was collected from the wild and 20 000 wet tonnes was cultivated, but by 1995 these amounts had changed to 6 000 and 37 000 wet tonnes, respectively. However, for cultivation there are still problems in artificial seed production, so instead, young fronds are collected from the natural beds and 3-4 are inserted in a rope at 10 cm intervals. Seeding ropes are attached to the main cultivation rope (Figure 58), which is kept at a depth of 2-3 m using flotation buoys along the rope and anchoring it to the seabed at each end - as described previously for Undaria. Cultivation is from November to May, mainly to avoid a clash with activities connected with wakame cultivation. Harvesting is in May-June. More convenient methods of farming are being tried, including vegetative reproduction.
After harvesting, it is washed with seawater (Figure 59) and dried in the sun (Figure 60). However, Hizikia is a very dark colour and contains higher than usual amounts of a pigment, phlorotannin, that gives it an astringent, bitter taste. Further processing involves boiling in water for 4-5 hours with another brown seaweed added, Eisenia bicyclis or Ecklonia cava. Boiling removes some of the pigment from Hizikia and it has been found that the addition of Eisenia or Ecklonia provides it with replacement colour. After boiling, the seaweed is steamed for 4-5 hours to remove the phlorotannins. Then it is cut into short pieces and sun-dried. The product is called hoshi hiziki. It is sold packaged in dried, black, brittle pieces that are soaked for 10-15 minutes before use. Typically it is cooked in stir fries, with fried bean curd and vegetables such as carrot, or it may be simmered with other vegetables.

FIGURE 57
Hizikia fusiformis, mature plants from cultivation.

C.H. SOHN, PUSAN

FIGURE 58
Hizikia fusiformis. The seeding rope (white) was attached to the main rope when the seedlings were small.

C.H. SOHN, PUSAN

Sun-dried hiziki is collected at local cooperatives and sold by auction to wholesalers, who later sell to processors. They prepare the hoshi hiziki by the boiling and steaming process and package it for retail sale.
For further details
More detailed information about the nutritive value of Hizikia is available in Nisizawa (1987) and Nisizawa et al. (1987).
Cultivation is described in Sohn (1998), with useful illustrations, and in Sohn (1999).
Limited processing information is found in Nisizawa (1987), Nisizawa et al. (1987) and Sohn (1998).

8.7 Mozuku (Cladosiphon okamuranus)

Mozuku (Cladosiphon okamuranus) is a brown seaweed that is harvested from natural populations in the more tropical climate of the southern islands of Japan (Kagoshima and Okinawa Prefectures). Cladosiphon grows in the sublittoral, mainly at depths of 1-3 m. In the 5-6 months from late October to April it grows from 1-2 cm to its full size of20-30 cm. It prefers reef flats in calm water, although a moderate water current is needed to supply sufficient nutrients.

FIGURE 59
Washing Hizikia fusiformis (Cheju Island, the Republic of Korea).

FIGURE 60
Sun drying Hizikia fusiformis (Cheju Island, the Republic of Korea).

Its life history involves an alternation of generations, with the seaweed being the sporophyte, while the alternate generation, the gametophyte, are microscopic plants. Cultivation involves collecting spores from the sporophytes and storing them in transparent polycarbonate tanks during summer. In autumn, seed nets are prepared and transferred to a nursery ground, preferably seagrass beds or similar sea beds with moderate currents. When young sporophytes have grown to 2-5 cm, the nets are moved to the main cultivation sites. These have a water depth of up to 3 m at low tide and the nets are placed 30-40 cm above the bottom. The plants are harvested after about 90 days, when they have grown to 30 cm. Harvesting is done by divers using a suction pump that draws the seaweed up and into a floating basket beside the attending boat. The harvested seaweed must be protected from sunlight. Processing for market involves cleaning and salting with 20-25 percent salt. It is stored to dehydrate for about 15 days, drained and sold in wet, salted form in packages ranging from 250 g to 18 kg.
After washing to remove the salt, it is used as a fresh vegetable, eaten with soy sauce and in seaweed salads. Due to increasing demand, cultivation was started around Okinawa Island in the 1980s. By 1995, production was 10 000 wet tonne/year and there was an oversupply. It has also been cultivated on the islands of Tonga in the Pacific, looking to an export market in Japan, but the oversupply there has stifled progress.
For further details
A full explanation of the life cycle and cultivation method is available in Toma (1993).

8.8 Sea grapes or green caviar (Caulerpa lentillifera)

There are many species of the genus Caulerpa, but Caulerpa lentillifera and C. racemosa are the two most popular edible ones. Both have a grape-like appearance and are used in fresh salads. They are commonly found on sandy or muddy sea bottoms in shallow protected areas. The pond cultivation of C. lentillifera has been very successful on Mactan Island, Cebu, in the central Philippines, with markets in Cebu and Manila and some exports to Japan. About 400 ha of ponds are under cultivation, producing 12-15 tonnes of fresh seaweed per hectare per year.
C. lentillifera (Figure 61) is the species best adapted to pond culture, although some strains of C. racemosa also give good yields. C. lentillifera is sensitive to changes of salinity, so pond areas must be placed away from any freshwater sources, and in the wet season in the Philippines surface drains are placed around the ponds to remove freshwater. The seaweed can tolerate a salinity range of 30-35 parts per thousand. Successful cultivation depends on good water management and the ponds must be designed so that tidal flows can be used to change the water in the ponds every second day. Water temperature can range between 25° and 30°C. Pond depth should be about 0.5 m and areas of about 0.5 ha are usual.
Planting is done by hand; about 100 g lots are pushed into the soft bottom at 0.5-1 m intervals. Sometimes broadcasting is used but this is not as efficient, the plants are loose on the bottom and can be moved by water motion induced by wind action on the surface. Key factors to control during growth are water exchange, weeding of other species of seaweed that would otherwise compete with the Caulerpa, and fertilization if the plants appear unhealthy or pale green to yellow in colour. Harvesting can commence about two months after the first planting; the seaweed is pulled out of the muddy bottom, but about 25 percent of the plants are left as seed for the next harvest. Depending on growth rates, harvesting can then be done every two weeks. The harvested plants are washed thoroughly in seawater to remove all sand and mud, then inspected, sorted and placed in 100-200 g packages; these will stay fresh for 7 days if chilled and kept moist. For local consumption, or air freight to Metro Manila, the seaweed may be packed in baskets lined with banana leaves; 20-30 kg of seaweed is placed on the leaves, the basket is topped with more banana leaves and covered with a plastic sack that is then fixed to the basket.

FIGURE 61
Caulerpa lentillifera (the Philippines).

For further details
A full description of pond culture of Caulerpa lentillifera and an analysis of the economics of a one-hectare farm can be found in Trono and Ganzon-Fortes (1988). However, that reference is out of print and may be difficult to locate. Other useful descriptions of the details of pond culture are in Trono and Toma (1993) and Trono (1998).

8.9 Dulse (Palmaria palmata)

Dulse, a red algae with leathery fronds (leaves) (Figure 62), is found in the eulittoral zone and sometimes the upper sublittoral. It is collected by hand by harvesters plucking it from the rocks at low tide. It is perennial and when either plucked or cut, new growth appears from the edge of the previous season's leaf. It is harvested mainly in Ireland and the shores of the Bay of Fundy in eastern Canada, and is especially abundant around Grand Manan Island, situated in the Bay of Fundy, in a line with the Canadian-United States of America border between New Brunswick and Maine. The harvest season here is from mid-May to mid-October. After picking, the seaweed is laid out to sun dry for 6-8 hours; if the weather is not suitable, it can be stored in seawater for a few days, but it soon deteriorates. Whole dulse is packed for sale in plastic bags, 50 g per bag. Inferior dulse, usually because of poor drying, is broken into flakes or ground into powder for use as a seasoning; sometimes it is added to corn chips. In Nova Scotia and Maine, dried dulse is often served as a salty cocktail snack and bar owners often offer it free - it induces thirst.

FIGURE 62
Dulse, Palmaria palmata. The smallest division on the scale is 1 mm, the large divisions are 1 cm.

J.M. JONES

In Ireland, it is sold in packages and looks like dark-red bundles of flat leaves. It is eaten raw in Ireland, like chewing tobacco, or is cooked with potatoes, in soups and fish dishes. One company in Northern Ireland is promoting its sale through pubs as a chewy, salty snack food, and through fruit and vegetable markets.
Dulse is a good source of minerals, being very high in iron and containing all the trace elements needed in human nutrition. Its vitamin content is also much higher than a vegetable such as spinach. In Canada, one company has cultivated it in land-based systems (tanks) and promotes it as a sea vegetable with the trade name "Sea Parsley". It is a variant of normal dulse plants, but with small frilly outgrowths from the normally flat plant. It was found by staff at the National Research Council of Canada's laboratories in Halifax, Nova Scotia, among samples from a commercial dulse harvester. For more information, go to www.oceanproduce.com. For those interested in some background information and opinions on why the North American dulse industry has not prospered, see Chopin (1998).

8.10 Irish moss or carrageenan moss (Chondrus crispus)

Chondrus crispus has already been discussed as a source of carrageenan, in Sections 6.2 to 6.4. Irish Moss has a long history of use in foods in Ireland and some parts of Europe. It is not eaten as such, but used for its thickening powers when boiled in water, a result of its carrageenan content. One example is its use in making blancmange, a traditional vanilla-flavoured pudding. In eastern Canada, a company is cultivating a strain of Chondrus crispus and marketing it in Japan as hana nori, a yellow seaweed that resembles another traditional Japanese seaweed that is in limited supply from natural resources because of overharvesting and pollution. First introduced to the Japanese market in 1996, the dried product, to be reconstituted by the user, was reported to be selling well at the end of 1999, with forecasts of a market valued at tens of millions of US dollars. It is used in seaweed salads, sashimi garnishes and as a soup ingredient.

8.11 Winged kelp (Alaria esculenta)

This large brown kelp grows in the upper limit of the sublittoral zone. It has a wide distribution in cold waters and does not survive above 16°C. It is found in areas such as Ireland, Scotland (United Kingdom), Iceland, Brittany (France), Norway, Nova Scotia (Canada), Sakhalin (Russia) and northern Hokkaido (Japan). In Ireland it grows up to 4 m in length and favours wave-exposed rocky reefs all around the Irish coast. Eaten in Ireland, Scotland (United Kingdom) and Iceland either fresh or cooked, it is said to have the best protein among the kelps and is also rich in trace metals and vitamins, especially niacin. It is usually collected from the wild and eaten by local people, and while it has been successfully cultivated, this has not been extended to a commercial scale.

8.12 Ogo, ogonori or sea moss (Gracilaria spp.)

Gracilaria species have already been discussed as sources of agar, in Sections 2.2 and 2.3.
Fresh Gracilaria has been collected and sold as a salad vegetable in Hawaii (United States of America) for several decades. The mixture of ethnic groups in Hawaii (Hawaiians, Filipinos, Koreans, Japanese, Chinese) creates an unusual demand and supply has at times been limited by the stocks available from natural sources. Now it is being successfully cultivated in Hawaii using an aerated tank system, producing up to 6 tonnes fresh weight per week. Limu manauea and limu ogo are both sold as fresh vegetables, the latter usually mixed with raw fish. In Indonesia, Malaysia, the Philippines and Viet Nam, species of Gracilaria are collected by coastal people for food. In southern Thailand, an education programme was undertaken to show people how it could be used to make jellies by boiling and making use of the extracted agar. In the West Indies, Gracilaria is sold in markets as "sea moss"; it is reputed to have aphrodisiac properties and is also used as a base for a non-alcoholic drink. It has been successfully cultivated for this purpose in St Lucia and adjacent islands.

8.13 Callophyllis variegata

In Chile, the demand for edible seaweeds has increased and Callophyllis variegata ("carola") is one of the most popular. Its consumption has risen from zero in 1995 to 84 wet tonnes in 1999. This red seaweed has a high commercial value but knowledge of its biology is restricted. In 1997, a new research project was funded, which should result in recommendations for the management of the natural resources and opportunities for cultivation.

8.14 Future prospects

The seaweeds eaten in large quantities in China, the Republic of Korea and Japan (nori, kombu nad wakame) are all in a state of full supply, if not oversupply, in those countries. Nori producers in Japan are looking for exports to United States of America and other countries to absorb their surplus production. This, taken with the experiences of the two companies that attempted nori production in United States of America, means it would not be advisable to invest in new production facilities for nori in the near future. Certainly any prospective investors in developed countries would first need to secure rights to all the cultivation areas they propose to use.
Those marketing wakame and other edible seaweeds in Europe, and France in particular, have shown that patience is needed to gain acceptance. However, the oversupply of wakame in the Republic of Korea has shown how new innovative products can expand a market. Similarly, there is something to be learned from the success of the two Canadian ventures, Sea Parsley and hana nori. Both are new products from seaweeds that have been accepted as human food for many decades. The success of their investors reflects both their ability to identify and exploit niche markets and the expertise to cultivate a consistent product.
The venture in Hawaii illustrates another approach that can be taken. Here there was an established market for fresh seaweeds but an unreliable supply from natural resources. By investing in the equipment and expertise for cultivation, a successful operation producing fresh edible seaweeds has been established. The Philippines experience with Caulerpa cultivation as a fresh vegetable is another illustration of using cultivation to widen a market first established from wild seaweed; it is surprising that this kind of enterprise has not been copied in other tropical countries.
Innovation, cultivation and niche markets: the combination of these three may lead to greater success for future investors, rather than attempts to break into the large markets for nori, kombu and wakame.
Finally, some useful ideas from D. Myslabodski (Great Sea Vegetables, United States of America. pers. comm.). Not everyone will jump at the opportunity of having a plate of Caulerpa with their salad or having dulse as a snack. He suggests a different approach to the use of seaweeds in human food: "sea farina". This is a food grade seaweed meal (ground dried seaweed) with a particle or mesh size dependent on the final application: fine for baking, coarser for use as salt substitute or condiment. This could be made on a small or large scale. There is a long list of sea plants that have been traditional sources of human food around the world and this information could be used as a reference for collection and cultivation. What would be the health benefits to people in developing countries if just 3 percent sea farina were added to the tortillas, pitas and breads of the world? Is there a market in developed countries for such a "natural" and "organically grown" additive to the normal diet? Properly dried sea vegetables and sea farina are stable for months, perhaps longer. They do not need to be frozen or refrigerated, and sea farina is very compact and so easy to transport.
A last word from Myslabodski and others in the food business. In the English language we have done ourselves a disservice calling it "seaweed": weeds are something we do not want, seaweed implies something negative about the product. When trying to convince others to eat it, "sea plants" or "sea vegetables" may be more appropriate words to describe it.

---

CARRAGEENAN

There are several carrageenans, differing in their chemical structure and properties, and therefore in their uses. The carrageenans of commercial interest are called iota, kappa and lambda.
Their uses are related to their ability to form thick solution or gels, and they vary as follows.

Iota	Elastic gels formed with calcium salts. Clear gel with no bleeding of liquid (no synaeresis). Gel is freeze/thaw stable.
Kappa	Strong, rigid gel, formed with potassium salts. Brittle gel forms with calcium salts. Slightly opaque gel, becomes clear with sugar addition. Some synaeresis.
Lambda	No gel formation, forms high viscosity solutions.

The carrageenan composition in red seaweeds differs from one species to another.

Chondrus crispus	mixture of kappa and lambda.
Kappaphycus alvarezii	mainly kappa.
Eucheuma denticulatum	mainly iota.
Gigartina skottsbergii	mainly kappa, some lambda.
Sarcothalia crispata	mixture of kappa and lambda.

7.1 Carrageenan production methods

There are two different methods of producing carrageenan, based on different principles.
In the original method - the only one used until the late 1970s-early 1980s - the carrageenan is extracted from the seaweed into an aqueous solution, the seaweed residue is removed by filtration and then the carrageenan is recovered from the solution, eventually as a dry solid containing little else than carrageenan. This recovery process is difficult and expensive relative to the costs of the second method.
In the second method, the carrageenan is never actually extracted from the seaweed. Rather the principle is to wash everything out of the seaweed that will dissolve in alkali and water, leaving the carrageenan and other insoluble matter behind. This insoluble residue, consisting largely of carrageenan and cellulose, is then dried and sold as semi-refined carrageean (SRC). Because the carrageenan does not need to be recovered from solution, the process is much shorter and cheaper.

7.1.1 Refined carrageenan and filtered carrageenan

Refined carrageenan is the original carrageenan and until the late 1970s-early 1980s was simply called carrageenan. It is now sometimes called filtered carrageenan. It was first made from Chondrus crispus, but now the process is applied to all of the above algae.
The seaweed is washed to remove sand, salts and other foreign matter. It is then heated with water containing an alkali, such as sodium hydroxide, for several hours, with the time depending on the seaweeds being extracted and determined by prior small-scale trials, or experience. Alkali is used because it causes a chemical change that leads to increased gel strength in the final product. In chemical terms, it removes some of the sulphate groups from the molecules and increases the formation of 3,6-AG: the more of the latter, the better the gel strength. The seaweed that does not dissolve is removed by centrifugation or a coarse filtration, or a combination. The solution is then filtered again, in a pressure filter using a filter aid that helps to prevent the filter cloth becoming blocked by fine, gelatinous particles. At this stage, the solution contains 1-2 percent carrageenan and this is usually concentrated to 2-3 percent by vacuum distillation and ultrafiltration.

FIGURE 44
Sun drying semi-refined carrageenan (alkali treated K. alvarezii).

FIGURE 45
Flow chart for the production of refined carrageenan (after Porse, 1998).

The processor now has a clear solution of carrageenan and there are two methods for recovering it as a solid, both rather similar to those described previously for agar production. An alcohol-precipitation method can be used for any of the carrageenans. A gel method can be used for kappa-carrageenan only, and the gel can be dehydrated either by squeezing or by subjecting it to a freeze-thaw process.
In the alcohol method, isopropanol is added until all the carrageenan is precipitated as a fibrous coagulum that is then separated using a centrifuge or screen (a fine sieve). The coagulum is pressed to remove solvent and washed with more alcohol to dehydrate it further. It is then dried and milled to an appropriate particle size, 80 mesh or finer. For the process to be economic the alcohol must be recovered, both from the liquids and the dryer, and recycled.
The gel method relies on the ability of kappa carrageenan to form a gel with potassium salts. The gel may be formed in various ways. For the freeze-thaw process it is convenient to form it as spaghetti-like pieces by forcing the carrageenan solution through fine holes into a potassium chloride solution. The fine "spaghetti" is collected and washed with more potassium chloride to remove more water, pressed to remove surplus liquid and then frozen. When allowed to thaw, separation of water occurs by synaeresis, the pieces are washed with more potassium chloride, chopped up and dried in a hot air dryer. Inevitably the product contains some potassium chloride. The alternative to freeze-thaw is to force water out of the gel by applying pressure to it, using similar equipment to that used for agar (Figure 10). After squeezing for several hours the sheets of gel are chopped, dried in a hot air dryer and milled to an appropriate particle size. Many agar processors are now using their equipment and similar techniques to produce kappa carrageenan as well.
Figure 45 summarizes the above processes.

7.1.2 Semi-refined carrageenan and seaweed flour

Semi-refined carrageenan (SRC) was the name given to the product first produced by the second method of processing noted in Section 7.1. This is the method in which the carrageenan is never actually extracted from the seaweed.
In the production of SRC, Kappaphycus alvarezii, contained in a metal basket, is heated in an alkaline solution of potassium hydroxide for about two hours. The hydroxide part of the reagent penetrates the seaweed and reduces the amount of sulphate in the carrageenan, increases the 3,6-AG so the gel strength of the carrageenan in the seaweed is improved. The potassium part of the reagent combines with the carrageenan in the seaweed to produce a gel and this prevents the carrageenan from dissolving in the hot solution. However, any soluble protein, carbohydrate and salts do dissolve and are removed when the solution is drained away from the seaweed. The residue, which still looks like seaweed, is washed several times to remove the alkali and anything else that will dissolve in the water. The alkali-treated seaweed is now laid out to dry; in hot climates, like the Philippines, usually on a large concrete slab (Figure 44). After about two days it is chopped and fed into a mill for grinding to the powder that is sold as SRC or seaweed flour.
The above process is summarized in Figure 46 (seaweed flour branch).
However, the seaweed flour is coloured, often has a high bacterial count and is not suitable for human consumption. Nevertheless it immediately found a large market in canned pet food because it is a good gelling agent and was so much cheaper than refined carrageenan. The temperatures used in the canning process destroy any bacteria so the high bacterial count in the SRC is not a problem. Sometimes the dried product is just chopped into pieces, not milled, and sold as a raw material to refined carrageenan processors. It is called alkali treated cottonii (ATC) or alkali treated cottonii chips (ATCC), or even simply cottonii chips. If this treatment is done in the country of origin of the seaweed, such as the Philippines or Indonesia, this means processors in Europe and United States of America have cheaper transport costs per tonne of carrageenan, compared with shipping dried seaweed. They have also left behind some waste products, which reduces their waste treatment costs.

FIGURE 46
Flow chart for the production of seaweed flour and PES/PNG carrageenans (after Bixler, 1996).

Kappaphycus alvarezii is used in this process because it contains mainly kappa carrageenan and this is the carrageenan that forms a gel with potassium salts. Iota-containing seaweeds can also be processed by his method, although the markets for iota carrageenan are significantly less than those for kappa. Lambda carrageenans do not form gels with potassium and would therefore dissolve and be lost during the alkali treatment.
The simplicity of the process means the product is considerably cheaper than refined carrageenan.
There is no alcohol involved that must be recovered, no distillation equipment to purify alcohol, no equipment for making gels, no refrigeration to freeze the gels, nor any expensive devices to squeeze the water from the gel.

7.1.3 Philippine natural grade (PNG) and processed Eucheuma seaweed (PES)

Producers in the Philippines developed a higher quality product, suitable for human consumption, by modifying the process just described for SRC.
After the alkali treatment and water washing, the product is chopped and treated with bleach to remove the colour (chopping improves penetration by the bleach, and bleach also helps to reduce the bacterial count). After washing to remove any bleach, the product is dried in a closed dryer. In this type of dryer, indirectly heated hot air passes up through a bed of the unground pieces or chips that are being carried through the dryer on a chain-type belt. This closed system dryer is usually sufficient to keep the bacterial count low enough to make a human-food grade product. If bacteria reduction is required, the dried chips can be milled and then washed with alcohol (ethanol) followed by vacuum evaporation to recover the alcohol. A simpler process is to treat the milled powder with superheated steam.
The above process is summarized in Figure 46 (PES/PNG carrageenan branch).
The product was originally called Philippine natural grade carrageenan (PNG).
Attempts to market this product as food grade in the United States of America and Europe resulted in strong opposition from the producers of refined carrageenan who did not wish to lose market share to this cheaper product. Eventually in the United States of America, the Food and Drug Administration declared it suitable for use in human food and to be labelled as "carrageenan", the same status as that of the refined product.
In Europe, both refined and PNG are permitted in human food, but carry different labels:

• refined carrageenan is labelled "carrageenan" and E-407; while
• Philippine natural grade is labelled "processed Eucheuma seaweed" or "PES", and E-407a.

So PNG and PES are the same grade of carrageenan.
The main difference between refined carrageenan and PNG is that PNG contains the cellulose that was in the original seaweed while in refined carrageenan this has been removed by filtration during the processing. Refined carrageenan will therefore give a clear solution, while PNG gives a cloudy solution. Where clarity of a user's product is of no consequence, PNG is suitable.
For further details
Detailed information on any methods of carrageenan extraction are not easy to find. As Stanley (1987) said, they are closely guarded as trade secrets by the several manufacturers. Some information can be found in Stanley (1987), Stanley (1990) and Therkelsen (1993).

7.2 Carrageenan producers and distributors

A summary of the capacity of carrageenan producers according to their broad geographical location is given in Table 8, and the principal producers and distributors are listed in the next section.
TABLE 8
Carrageenan processors. Capacity in tonnes (2001)

	Alcohol process	Gel process	PES	Total	%	ATC 1
Europe	8 100	5 000	500	13 600	32
Americas	4 700	3 350	1 100	9 150	21
Asia-Pacific	2 000	8 280	9 900	20 180	47	16 000
Total	14 800	16 630	11 500	42 930		16 000

¹ ATC = Alkali treated cottonii or seaweed flour, used mainly for pet food.
Source: H. Porse, CP Kelco. ApS, 2002, pers. comm

7.2.1 Refined carrageenan producers and distributors

_________________________________
CP Kelco ApS
Ved Banen 16
4623 Lille Skensved
Denmark
Tel: [INT+45] + 5616 5616
Fax: INT+45] + 5616 9446
Website: www.cpkelco.com
_________________________________
Shemberg Marketing Corporation
corner Lapu-lapu and Osmena Boulevard
Cebu City
The Philippines
Tel: [INT+63] + (32) 346 0866
Fax: [INT+63] +(32) 346 1892; 346 0863
_________________________________
Shemberg Biotech Corporation
Carmen, Cebu City
The Philippines
Tel: [INT+63] + (32) 254 9380
Fax: [INT+63] + (32) 254 9388
_________________________________
Ingredients Solutions Inc.
PO Box 407
Searsport, ME 04974-0407
United States of America
Tel: [INT+1] + (207) 548 0074
Fax: [INT+1] + (207) 548 2921
_________________________________
Marcel Carrageenan Corporation
926 Araneta Avenue
Quezon City 1104
Philippines
Tel: [INT+63] + (2) 712 2631/2640/2841
Fax: [INT+63] + (2) 712 1989/5879
_________________________________
FMC Biopolymer
1735 Market Street
Philadelphia PA 19103
United States of America
Tel: [INT+1] + (215) 299 6000
Fax: [INT+1] + (215) 299 5809
Websites: www.fmc.com;
www.fmcbiopolymer.com
_________________________________
Degussa Texturant Systems
Lise-Meitner-St.34
85354 Freising
Germany
Tel: [INT+49] + (8161) 548 266
Fax: [INT+49] + (8161) 548 582
Website: www.texturantsystems.com
_________________________________
Danisco Cultor
Edwin Rahrs Vej 38
8220 Brabrand
Denmark
Tel: [INT+45] 89 43 50 00
Fax: [INT+45] 86 25 06 81
Website: www.daniscocultor.com
_________________________________
Rhodia Food
40, rue de la Haie-Coq
93306 Aubervilliers Cedex
France
Tel: [INT+33] 1 53 56 50 00
Fax: [INT+33] 1 53 56 55 55
Website: www.rhodiafood.com
_________________________________
Gelymar S.A.
Av. Pedro de Valdivia Norte 061
Providencia, Santiago
Chile
Tel: [INT+56] + 2 230 9400
Fax: [INT+56] + 2 232 1544
_________________________________
CEAMSA
"Les Gandaras", PO Box 161
36400 Porrino (Pontevedra)
Spain
Tel: [INT+34] + (986) 344 089
Fax: [INT+34] + (986) 336 621
Website: www.ceamsa.com
_________________________________
Hispanagar, S.A.
Avenida López Bravo, 98
Polígono de Villalonquejar
Apartado Postal 392
08080 Burgos
Spain
Tel: [INT+34] + (947) 298519
Fax: [INT+34] + (947)298518
Website: www.hispanagar.net
_________________________________
Ina Food Industry Co., Ltd.
574 Tsurumakicho, Waseda
Shijuku
Tokyo 162
Japan
Tel: [INT+81] + (3) 3235 8861
Fax: [INT+81] + (3) 3235 8863
_________________________________
Myeong Shin Chemical Ind. Co., Ltd.
439-13, Soju-Ri, Ungsang-Up,
Yangsan-gun, Kyeong-Nam,
The Republic of Korea
Tel: [INT+82] + (55) 389 1001
Fax: [INT+82] + (55) 389 0478
(Head Office and carrageenan factory)
_________________________________
Soriano S.A.
9 de Julio 745
9100 Trelew
PCIA Chubut
Argentina
_________________________________
Chuo Food Materials Co.Ltd
Osaka
Japan
Marine Science Co Ltd
Higashi-kanda Towa-building 6F, 2-3-3,
Higashi-kanda
Chiyoda-ku
Tokyo 101-0031 Japan
Tel: [INT+81] + (3) 3865 3485
Fax [INT+81] + (3) 3865 3450

7.2.2 PNG and PES and seaweed flour producers and distributors

_________________________________
Ingredients Solutions Inc.
PO Box 407
Searsport ME 04974-0407
United States of America
Tel: [INT+1] + (207) 548 0074
Fax: [INT+1] + (207) 548 2921
_________________________________
Marcel Carrageenan Corporation
926 Araneta Avenue
Quezon City 1104
The Philippines
Tel: [INT+63] + (2) 712 2631/2640/2841
Fax: [INT+63] + (2) 712 1989/5879
_________________________________
Shemberg Marketing Corporation
corner Lapu-lapu and Osmena Boulevard
Cebu City
The Philippines
Tel: [INT+63] + (32) 346 0866
Fax: [INT+63] + (32) 346 1892/0863
_________________________________
Quest International Philippines Corp.
Mactan Export Processing Zone,
G/F SFB Pt. 1,
Lapu-Lapu City
Cebu
The Philippines.
Tel: [INT+63] + (32) 340 0322/0319/0764
Fax: [INT+63] + (32) 340 0328/0324
_________________________________
FMC Corporation
Ouano Compound
Looc, Mandaue City
6014 Cebu
The Philippines.
Tel: [INT+63] + (32) 85097, 346 0882
Fax: [INT+63] + (32) 54098, 3461182/1187
_________________________________
Geltech Hayco, Inc.
2211 Taft Avenue
Metro Manila
The Philippines.
Tel: [INT+63] + (2) 521 3094, 571 306
Fax: [INT+63] + (2) 526 0591
_________________________________
TBK Manufacturing Corp.
Brgy 76, Hollywood, Nula-tula
Tacloban city
6500 Leyte
The Philippines
Tel: [INT+63] + (2) 727 6891
Fax: [INT+63] + (2) 725 5163
_________________________________
Iberagar S.A.
Estrada Nacional 10, km. 18
Coina
Portugal
Tel: [INT+35] + (121) 210 9252
Fax: [INT+35] + (121) 2109255
Website: www.iberagar.com
_________________________________
P.T. Surya Indoalgas Jln Kedungdoro - 60
Surabaya 60251
Indonesia
Tel: [INT+62] + (31) 548 2003
Jakarta office:
Tel: [INT+62] + (21) 564 7270
Fax: [INT+62] + (21) 564 9285
_________________________________
C.V. Cahaya Cemerlang
Jln S. Cerekang - 16(34)
Ujung Pandang
Indonesia
Tel: [INT+62] + (411) 31 53 58
Fax: [INT+62] + (411) 31 82 27
_________________________________
P.T. Gumindo Perkasa Industri
Wisma UIC, 2nd Floor
Jln Jend Gatal Kav 6-7
Jakarta 12930
Indonesia
Tel [INT+62] + (21) 520 0832
Fax: [INT+62] + (21) 529 60004
_________________________________
P.T. Asia Sumber Laut Indonesia
Jln Rajawali 64 K
Surabaya 60176
Indonesia
Tel: [INT+62] + (31) 357 7892
Fax: [INT+62] + (31) 357 7901
For further information about the Philippines contact:
Secretary General
Seaweed Industry of the Philippines
T.R. Martinez Bldg, 2nd Floor
Osmena Blvd
Cebu City,
The Philippines
Tel: [INT+63] + (32) 253 7433
Fax: [INT+63] + (32) 254 8780
For further details about Indonesia and other Indonesian companies contact:
Indonesian Seaweed Industry Association (APBIRI) at:
Asosiasi Pengusaha Budidaya dan Industri Rumput Laut Indonesia (APBIRI)
BPPT Lt. 13
Jl. MH Thamrin No. 8
Jakarta Pusat 10340
Indonesia
Tel: (62) 21 322430

7.3 Carrageenan uses

Before discussing uses, some explanations of the properties of carrageenans are necessary.
Both kappa and iota carrageenan form gels with potassium and calcium salts. Aqueous solutions of both carrageenans must be heated above 60°C for the carrageenan to dissolve, and after addition of the salt, the gel forms as the solution cools. For kappa, as little as 0.5 percent in water and 0.2 percent in milk is sufficient to form gels.
Kappa forms gels most strongly with potassium salts, followed by calcium salts. Potassium gives a rigid, elastic gel while calcium produces a stiff, brittle gel. Kappa gives the strongest gels of all carrageenans, but they are also the ones most likely to bleed (most subject to synaeresis). This liability can lessened in a couple of ways. If iota and lambda carrageenans are blended in with the kappa, bleeding can be reduced, so will also the rigidity and brittleness of the gel; however, the gel strength may also be lowered. Synaeresis can also be reduced by adding locust bean gum (obtained from the seeds of the carob tree (Ceratonia siliqua), growing in Spain, Italy, Cyprus, etc.). This gum also allows the amount of kappa to be reduced while still maintaining the same gel strength. The kappa can be reduced to one-third of the concentration that would be needed if no locust bean gum were used. The resulting gels are more resilient than those with kappa alone. As long as locust bean gum is cheaper than kappa there is also an economic advantage. However, the cost of locust bean gum can fluctuate depending on the harvest and demand.
Iota forms gels most strongly with calcium salts, followed by potassium salts - the reverse of kappa reactivities. Calcium gels are soft and resilient and are virtually free of bleeding. They can be frozen and thawed without destroying the gel. They show an unusual property for a gel: thixotropic flow; this means the gel can be stirred and it will flow like a thick liquid, but if left to stand it will gradually reform a gel.
A similar thixotropic behaviour is found with very low concentrations of kappa carrageenan in milk; a weak gel forms that is easily made to flow by shaking. The weak gel is strong enough to suspend fine particles in the milk, such as cocoa in chocolate milk.
Protein reactivity of carrageenans is an important property that is utilized in several applications. Carrageenan molecules carry negative charges; this is what enables them to combine with positively charged particles like the potassium found in potassium salts. They can also combine with positively charged proteins. Carrageenan will combine with the protein in milk (casein) to form a three-dimensional gel network. The exact nature of the interaction of proteins with carrageenans appears to be more complex than this simple explanation, and the interested reader can find more detail in the references suggested in Section 7.3.8.

7.3.1 Dairy products

The main applications for carrageenan are in the food industry, especially in dairy products.
Frequently, only very small additions are necessary, 0.01-0.05 percent. For example, kappa carrageenan (at 0.01-0.04 percent) added to cottage cheese will prevent separation of whey, and a similar amount added to ice cream also prevents whey separation that may be caused by other gums that were added to the ice cream to control texture and ice crystal growth. The cocoa in chocolate milk can be kept in suspension by addition of similar amounts of kappa; it builds a weak thixotropic gel that is stable as long as it is not shaken strongly. Dry instant chocolate mixes, to be mixed with water or milk, can have improved stability and mouth feel using lambda or a mixture of carrageenans.
Lambda or a mixture can also improve liquid coffee whiteners by preventing the separation of fat; these applications require 0.2-0.3 percent additions, but much smaller quantities will prevent fat separation in evaporated milks. Those small containers of UHT sterilized milk found in the refrigerators of some hotels may have kappa added to prevent fat and protein separation. Lambda or kappa may be added to natural cream to help maintain the lightness (incorporated air) if it is whipped. Many more uses in milk and dairy products can be found in the references below.

7.3.2 Water-based foods

With the appearance of bovine spongiform encephalopathy (BSE, or mad cow disease) and foot-and-mouth disease, efforts have been made to find suitable substitutes for gelatin. Gelatin jellies have long been favoured because they melt at body temperature, giving a smooth mouth feel and easy release of flavours. However, if they are stored for a day or two, they toughen and are less pleasant to eat. Gels made from iota carrageenan have the disadvantage of a high melting temperature, so they are not as smooth to eat as gelatin gels. They do not melt on hot days and do not require refrigeration to make them set, so these are advantages in hot or tropical climates, and a further advantage is that they do not toughen on storage. In the last two years there have been several claims by food ingredients companies for products, made from a mixture of hydrocolloids, that imitate the properties of gelatin. Carrageenan producers find that by combining various carrageenans with locust bean gum, konjac flour and starch, they can provide a variety of melting and non-melting gels and gel textures to meet the requirements of most of their clients. Long-life refrigerated mousse desserts, based on carrageenan and pectin rather than gelatin, are suitable for vegetarians and some ethnic groups.
Conventional fruit jellies are based on pectin and a high sugar content to help set the jelly. In a low- or non-calorie jelly the pectin must be replaced, and mixtures of kappa and iota have proved to be suitable. Fruit drink mixes to be reconstituted in cold water contain sugar (or aspartame), acid and flavour. Addition of lambda carrageenan gives body and a pleasant mouth feel. Sorbet is a creamy alternative to ice cream with no fat; use of a mixed kappa and iota together with locust bean gum or pectin provides a smooth texture to the sorbet.
Low-oil or no-oil salad dressings use iota or kappa to help suspend herbs, etc., and to provide the mouth feel that is expected from a normal salad dressing. The low oil content of reduced-oil mayonnaise normally gives a thin product, rather like a hand lotion; additives are needed to thicken it and to stabilize the oil-in-water emulsion. A combination of carrageenan and xanthan gum is effective. Xanthan gum is made by a bacterial fermentation process; its development was pioneered in the early 1960s by the Kelco Company, then the largest producer of alginate; it is now an accepted and widely used food additive. The interaction of carrageenan and protein can be used in the clarification of beer, with the complex formed precipitating from the wort. More water-based applications of carrageenan are given in the references below.

7.3.3 Meat products

In preparing hams, addition of carrageenan to the brine solution used in pumping improves the product because the carrageenan binds free water and interacts with the protein so that the soluble protein is retained. For successful penetration, the brine solution must have a low viscosity, but dissolved carrageenan would increase the viscosity. The carrageenan is therefore dispersed in the water after the brine salts are added; the carrageenan does not dissolve because of the high salt concentration, but as the ham cooks it does dissolve and is then effective.
There is a growing consumer demand for pre-cooked poultry products such as chicken and turkey pieces. Poultry processors were concerned about the loss of water during cooking (this lowered their yield per unit weight of product) and the loss in texture and eating quality that resulted. By injecting a brine containing salt, phosphate and carrageenan into the muscle of the meat, these problems are overcome. As the meat cooks, the carrageenan binds water within the poultry muscle and improves texture and tenderness. The processors are pleased because they now have a higher yield; in fact they find that he can even add some extra water to the poultry and it will be retained. The consumer receives a better product. The carrageenan producer is pleased because about 0.5 percent carrageenan is added, much more than the 0.05-0.1 percent used in dairy products. The future looks bright for this kind of application in meat products.
Hydrocolloids are being tried as fat replacements in low-fat products, with varying degrees of success. When fat or salt are reduced, meat and poultry can suffer loss of tenderness, juiciness and flavour. Low-fat products formulated with phosphates and carrageenan can have the juiciness and tenderness restored. Kappa carrageenan has been used with some success in replacing half the normal fat in frankfurters. Reduction of fat in ground meat products like hamburgers results in a different mouth feel and dry taste, which consumers do not always accept. Iota can be mixed with fresh ground beef and when cooked it provides fat-like characteristics and moisture retention that make the product more acceptable. This was the basis for McDonald's "MacLean" hamburger.

7.3.4 Pet food

This is the largest application for SRC, known as seaweed flour (see Section 7.1.2), using about 5 500 tonnes annually. Refined carrageenan could also be used, but its cost is too high and seaweed flour is about one-quarter of its price. Seaweed flour becomes an even better proposition because when combined with locust bean gum, less carrageenan is required, but this combination still gives an excellent product and it is very affordable. The meat used in canned pet foods is usually waste cuts from the abattoir. It is chopped into chunks or smaller pieces, mixed with water, flavours, seaweed flour (kappa carrageenan) and locust bean gum, canned and cooked. The two hydrocolloids help to bind the meat together and, depending on the concentrations used, either provide a thickened gravy around the meat pieces or a flavoured jelly, either of which enhances the appearance of the product as it is removed from the can. Konjac (or konjaku) gum, made from the konjac tuber or elephant yam (Amorphophallus konjac), can be used in place of locust bean gum. Konjac gels are clearer than locust bean gels and can help with costs when the price of locust bean gum rises, as it does occasionally.

7.3.5 Air freshener gels

When you need to improve the odours in your room, air freshener gels are one of the products available at supermarkets. They are made from kappa carrageenan, a potassium salt, water and perfume. When mixed, the perfumed gel forms and it is moulded to a shape to fit the holder. When purchased, the holder is sealed; to use, the holder is opened slightly and the moisture plus perfume are gradually released from the gel. Eventually the gel dries out leaving a small residue in the holder, which is then discarded. About 200 tonne/year of seaweed flour grade of carrageenan is the estimated consumption for this application.

7.3.6 Toothpaste

The essential ingredients in toothpaste are chalk or a similar mild abrasive, detergent, flavour, water and a thickening agent that will provide enough body to the paste to ensure that the abrasive is kept in suspension and that there is no separation of water. A thixotropic thickener is preferable, i.e. that has gel-like properties when allowed to stand but that will flow when pressure is applied to it. Iota carrageenan, at about 1 percent, is one of the most useful thickening agents, it meets the above criteria and gives a paste that is easily rinsed from the toothbrush. When the size of the toothpaste market is considered, even at 1 percent concentration this represents a large market for iota.

7.3.7 Immobilized biocatalysts

This application was discussed for alginates in Section 5.3.3. Carrageenan gels are another medium for immobilizing enzymes or whole cells. Kappa carrageenan gives the strongest gels and beads made from this show sufficient mechanical strength for packing in columns, and yet they are permeable to most substances.

7.3.8 For further details

More information about the properties and applications of carrageenans can be found in the following references, the first two of which are probably the most useful: Stanley (1990), Therkelsen (1993), Nussinovitch (1997), Stanley (1987).
For quick reference to a list of uses and the concentrations of carrageenan required, see Tables 3.4 and 3.5 in Thomas (1997).

7.3.9 Refined grade vs natural grade

Natural grade carrageenan is cheaper to make and requires a smaller capital outlay, therefore its price is lower than the refined or filtered grade. Natural grade is now approved for human use in most applications and jurisdictions. For a very useful and interesting discussion of the pros and cons of refined versus natural grades in regard to their purity, composition, and comparative performance in various applications, see Bixler (1996).

7.4 Markets and marketing of carrageenan

A summary of carrageenan markets is shown in Table 9. The total market has a value of about US$ 300 million. The marketing of carrageenan poses similar problems to those previously described in Section 5.4 for alginate. The original companies invested heavily in processing equipment and provided strong research and development facilities to assist customers and promote sales. These companies are now part of large multinationals and have a strong commitment to selling the refined carrageenan that they have always produced, and they operate at about 80-85 percent capacity. With the introduction of the simpler processing required for seaweed flour, many small companies entered that market, which required very little R&D because sales were mainly to pet food producers who knew exactly what they wanted and how to use it. Some of these companies then expanded their operations to produce the PES/PNG grade for human consumption. They make a few basic kappa and iota carrageenans for use in meat products, and to a lesser degree in dairy products. However, they lack the technical marketing skills to sell their products against the larger multinationals. These smaller companies are mainly in the Philippines and Indonesia, and operate at probably about 50 percent capacity and some are possibly struggling to survive. Despite this, new production facilities continue to be built in China and eastern Africa.
While there are difficulties in production of carrageenan, marketing can be even more difficult without adequate technical expertise to assist customers in the use of the product. Producers of refined carrageenan are not especially interested in selling the less expensive PES grade if such sales are going to replace sales of their refined grade. So there are opportunities for PES producers to penetrate the human food market with their less expensive product, if they are willing to invest in the technical expertise needed to service those sales. This has already occurred in the United States of America, where about 20 percent of the market is now PES grade. There appear to be similar opportunities awaiting PES producers in European markets that are still predominantly users of the refined grade (H.R. "Pete" Bixler, 2002, pers. comm.).
TABLE 9
Carrageenan markets (2001)

Application	tonnes	%
Dairy	11 000	33
Meat and poultry	5 000	15
Water gels	5 000	15
PES food grade	8 000	25
Toothpaste	2 000	6
Other	2 000	6
Total	33 000	100

Source: H. Porse, CP Kelco ApS, 2002, pers. comm.

7.5 Future prospects

In developed markets, such as the United States of America, Europe and Japan, all known applications are almost fully exploited. There could be some expansion by replacement of some of the gelatin market because of health concerns about bovine spongiform encephalopathy, but also due to a growing vegetarian population. Elderly people tend to use more processed foods in their diets and as this population increases so too will carrageenan consumption. Taking these factors into account, a 2-4 percent growth per annum can be expected in developed countries, and there the market splits about 50:50 between dairy and meat applications.
In areas such as Central and South America, Eastern Europe and Southeast Asia, growth will be stronger. Here the per capita consumption of carrageenan should increase by 50 percent over the next five years, due to market penetration alone. Allowing for population growth and assuming a moderate economic growth, an expansion of carrageenan consumption by 5-7 percent per annum is likely. At present the market is split into approximately 20 percent dairy and 80 percent meat applications, but this is likely to change with a gradual increase in the dairy foods market (H.R. "Pete" Bixler, 2002, pers. comm.).
For further details, see Bixler (1996), who discusses recent developments in the manufacturing and marketing of carrageenan and is excellent reading for anyone interested in obtaining an overall view of the carrageenan industry.