Marine algae have been utilized by man since prehistoric times as food, drugs or raw materials for chemicals; however, their more concentrated exploitation dates back only to the past 50 years or so. The discovery, isolation and purification of polysaccharides in the brown and red algae with characteristics favorable for different industrial applications created such a demand for these plants that worldwide shortage resulted, causing a keen competition among nations for the control of natural growing beds. Calculations are presented on the total potential world supply of harvestable algae and alternative solutions for satisfying the growing demands of the phycocolloid industries are discussed, including the current efforts to grow algae under controlled conditions for predictable harvests. The feasibility of such aquaculture ventures is evaluated and the pros and cons of creating algae factories are pointed out.


Marine algae are lower plants restricted to the salt water environment. They range in size from the microscopic unicellular organisms to the largest plants on the earth. Certain groups of them reach considerable dimensions and are called kelps in general.

According to their pigmentation, one Distinguishes among green, brown and red algae. All three groups are quite distinct and were already recognized by the Romans. Different uses date back to early historic times, both as food and medicaments. The brown algae were found to accumulate large quantities of iodine in their bodies, and dried weeds were already used in ancient China for the treatment of goiter. Some green algae are still cooked especially by Oriental people - into soups or made into salads) while red algae are smoked and sold as a delicacy in many of the Nordic countries. These uses of algae, however, did not warrant their large-scale exploitation. Only the discovery in this century that both the brown and red algae contain substances which are relatively easy to extract and have characteristics useful in different applications, lead to the foundation of what might be termed seaweed industry.

Most of the marine algae have a highly slippery consistency, which is due to mucous substances which they manufacture in their cells and secrete toward the environment. These substances serve the protection of the plants and all have one common characteristic -- they are made up of long polymers of different sugars.

Since they will produce a colloidal system in water, they fall into the category of hydrocolloids and since. They are obtained from algae) the Greek name of which is Phykos, they are termed phycocolloids. In modern industry there are basically three such colloids which are Widely utilized: [1] algin, or alginic acid) and its different salts obtained exclusively from brown algae; [2] agar-agar, produced by certain red algae and [3] carrageen in, extracted from other red algae.

Alginates are widely utilized in different foods for the high viscosity solutions they produce where such requirement is present, as in creams, to which they impart a better whipping ability.

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