Carrageenans

Chrondrus crispus: Carrageen mossCarrageenan is a general name for polysaccharides extracted from certain kinds of algae which are built up, in contrast to agar, from D-galactopyranose units only.

History

Dawson Turner, writing in his 4-volume work, British Fuci, in 1819 commented on Chondrus crispus (as Fucus crispus): that it will "...melt on boiling and afterwards harden into a gelatine, which I do not
despair of seeing hereafter employed to useful purposes, though I have
hitherto failed in my efforts to render it of service".

The use of such an extract from Chondrus crispus was in fact first described in Ireland around 1810, when it was recommended as a cure for respiratory ailments. The name “carrageen" for this species seems ot have been introduced around 1829 (Mitchell & Guiry 1983), and probably came from Carrigan Head in Co. Donegal in north-western Ireland. “Carrigan or Carrageen” is a common name throughout Ireland, not surprisingly since it means “Little Rock”. The use of Irish or Carrageen Moss spread from Ireland to New England, USA, probably via the Irish migrants fleeing the potato famines of the 18th and 19th centuries. A small processing industry developed there that expanded enormously during World War II, mainly to replace agar, the supply of which from Japan adn elsewhere had been cut off by the war. After the war, carrageenan gradually became a major force in the food-additives business, and is now the leading seaweed-extract on the world’s markets.

Whats it for?

Carrageenans are ideal food additives: they have a range of gelling and emulsifying properties ranging from a soft slime to a brittle gel that one could nearly walk upon. And you would be literally walking on water, as the percentage carrageenan would be as low as 4%. They also have a high reactivity with a range of materials including, most importantly, milk proteins, being widely used at low concentrations in dairy products to prevent fractionation of milk constituents.  In fact, a major application is found in chocolate milk, a very popular daily drink in the USA, and now spreading elsewhere. Carrageenans are also very good at keeping chocolate in suspension. So pervasive are seaweed polysaccharides now that it is highly likely that you have eaten carrageenan or some other seaweed product in more than one product over the last 24 hours. Just don’t tell your friends!

The main commercial sources of carrageenan used to be the subtidal Irish Moss beds in the cold-water Maritime Provinces of Canada where up to 65,000 wet tonnes of moss were gathered annually in the 1970s. The bulk of the harvest is collected using long-handled rakes and specially-designed dredges from small boats and currently amounts to about 35,000 wet tonnes. The seaweed is then dried, either by spreading and air-drying or by using rotary dryers, and exported to the USA and Denmark for processing.

However, various market requirements and problems with supply led to the development of an aquaculture industry for other warm-water carrageenan-producers, such as Eucheuma and Kappaphycus. This first originated in the Philippines as a simple process of tying vegetative fragments of the plants onto monolines (strong nylon line) which are attached to stakes or rafts, allowed to grow for several weeks and the product is then harvested by hand and dried. Red algae are generally totipotent, so that quite small fragments will grow into entirely new plants. This was an ideal industry for coastal communities, and the cultivation techniques rapidly spread to south-eastern Asia and around the Indian Ocean rim.  Now the industry uses a variety of sources of red algae for the production of different types of carrageenan with hand-collected plants from Chile, eucheumoid plants from the Philippines and the Indian Ocean, and Carrageen Moss from Canada. Quite a mixed bag of red seaweed types is necessary to produce the blended products now demanded by the industry and the consumer in their ever increasing search for new processed and convenience foods.

Processing now takes place in the Philippines, particularly of PGC ("Philippines Grade Carrageenan"), now an acceptable subsititute for refined carrageenan in a range of applications.The main producers of refined carrageenan are the USA, France, Denmark and the Philippines. Small amounts of carrageenan were produced for a time in Ireland (Waterford and Cork), but imported weed or crude carrageenan was the main raw material.

Carrageenan is used in processed foods for stabilization, thickening, and gelation. It has been successfully used by the food industry in the US since the 1950s, and with increasing demand driven by the consumers' need for convenience, appealing food textures, advances in food processing, and new food products. It is used worldwide to enhance ice creams, chocolate milk, custards, cheeses, jellies, confections, meats, and protein drinks. Carrageenan is an approved food additive. Carrageenan has found an interesting use as an effective lubricant during sex. In addition to reducing friction in sensitive areas, it has anti-microbial and antiviral properties, and is an effective carrier for anti-retroviral drugs in HIV prevention and treatment.

Shortages of carrageenan-producing seaweeds suddenly appeared in mid-2007, resulting in doubling of the price of carrageenan; some of this price increase is due to increased fuel costs and a weak dollar (most seaweed polysaccharides are traded in dollars). The reason for weed shortages are less certain: perhaps it is a combination of environmental factors, sudden increases in demand, particularly from China, and some market manipulation by farmers and traders.

Summary of uses

  • Processed Meat, Poultry and Seafood. Water binding, increased product yields, improved texture, fat replacement, meat/seafood analog binding.
  • Dairy Products (chocolate milk, frozen desserts, UHT milks, flans, puddings, low-fat cheese, cheese analogs). Provides cocoa suspension, milk stability, emulsion stability, milk gelling.
  • Cold Milk Powders (diet powder mixes, nutritional beverage mixes). Provides body and mouthfeel, suspends solids.
  • Water Gel Desserts. Provides wide range of textures and flavor release, all without the need for refrigeration.
  • Toothpaste. Provides structure without masking flavors, resistant to enzymatic breakdown.
  • Pet Foods. Binds water, provides structure and prevents fat separation in canned, retorted products.
  • Controlled Release Products (air freshener gels). Provides structure and controlled release of active ingredients such as perfume in a water-gel base.
  • More information

Eucheuma cultivationIs carrageenan safe?

You may see references in magazines and on the Internet that caution consumers against the consumption of carrageenan due to concerns about the potential for gastrointestinal effects (including malignancies). These cautions were based on the conclusions of a literature review by Dr. Joanne Tobacman and published in Environmental Health Perspectives in October 2001. Recent information has been published by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) that should allay your concerns about the consumption of carrageenan.

Overall, the JECFA concluded that there was no concern to the continued consumption of carrageenan and assigned it to the group "Acceptable Daily Intake - not specified". This classification is used when the JECFA has determined that a food additive does not represent a hazard to health. It also allows for the use of the additive at the level necessary to achieve the technical or functional effect in food, also referred to as the level of Good Manufacturing Practices (GMP). The complete report of this review was made publicly available in 2003 and therefore post dates the review by Dr. Tobacman.

Summary of JECFA Reports

In 2001 the Joint FAO/WHO Expert Committee on Food Additives (JECFA) completed a re-evaluation of carrageenan that began in 1998. The JECFA is an independent international body of expert scientists that functions under the auspices of the Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO). Members of the JECFA Committee that reviewed carrageenan included representatives of universities and government agencies of the following countries: Norway, Australia, Canada, Finland, United States (FDA), Japan, Netherlands, Denmark, France, and the United Kingdom. During the course of the re-evaluation, the JECFA specifically reviewed the matter of the potential for gastrointestinal effects from ingestion of carrageenan. This included an evaluation of the effects of stomach flora on carrageenan, food processing conditions on carrageenan and the degradation of carrageenan in the stomach. Throughout the course of the re-evaluation, the JECFA considered genotoxicity studies, metabolism, reproduction and developmental toxicity, and short term and long-term mammalian feeding studies (including a 7.5 year feeding study in monkeys). The JECFA also considered information about the current understanding of the concept of cell proliferation and promotion of tumors.

In their review, the JECFA correlated carrageenan feeding levels (and effect levels) in test animals to human intake of carrageenan. This is lacking in the Tobacman review article. The JECFA estimated that the human intake of carrageenan is 30-50 mg/person/day. However, the JECFA concluded that based on the rat studies, if effects from ingestion of carrageenan were observed, the levels of ingestion far exceeded those of human consumption. For example, the JECFA noted that no proliferative effect of carrageenan in the colon mucosa was observed at 1.5% carrageenan in the rat diet. This corresponds to an intake of carrageenan of 750 mg/kg body weight per day, which far exceeds the aforementioned estimated human intake. To put this consumption level in perspective, this carrageenan intake level of 750 mg/kg body weight/day corresponds to a daily consumption of 58 gallons of chocolate milk per day by a 150 lb person!

The fact that proliferative effects were seen at 2.6% in the diet is moot because the estimated carrageenan consumption is below the threshold concentration for these effects. Further, the JECFA also noted that at 5% in the diet of rats, carrageenan did not act as at tumor promotor. Effects seen at exceptionally high levels of exposure to carrageenan were determined to be caused by altered toxicokinetics. See the adjacent table for a comparison of the estimated human carrageenan intake and the experimental carrageenan intakes noted in the JECFA review.

Overall, the JECFA concluded that there was no concern to the continued consumption of carrageenan and assigned it to the group "Acceptable Daily Intake – not specified". This classification is used when the JECFA has determined that a food additive does not represent a hazard to health. It also allows for the use of the additive at the level necessary to achieve the technical or functional effect in food, also referred to as the level of Good Manufacturing Practices (GMP). The complete report of this review was made publicly available in 2003 and therefore post dates the review by Dr. Tobacman.

Production

Carrageenan processors have fueled the development of Kappaphycus alvarezii ("cottonii" to the trade) and Eucheuma denticulatum ("spinosum" to the trade) farming in several countries including the Philippines, Indonesia, Malaysia, Tanzania, Kiribati, Fiji, Kenya, and Madagascar; total market volume now exceeds 140,000 commercially dried tons per annum at a value of more than $70 million. Primarily wild-harvested genera such as Chondrus, Furcellaria, Gigartina, Sarcothalia, Mazzaella, Iridaea, Mastocarpus and Tichocarpus are also mainly produced as carrageenan raw materials;  producing countries include Argentina, Canada, Chile, Denmark, France, Japan, Mexico,  Morocco, Portugal, North Korea, South Korea, Spain, Russia and the USA (see www.surialink.com). World carrageenan production exceeded 50,000 tonnes in 2009 with a value of over US$527 million (Bixler & Porse 2010).

Thanks

Thanks to Harris 'Pete' Bixler, Ross Campbell and Kevin Philp for some of the information presented here.

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