ABSTRACT
The term “seaweed” (also known as kelp) is the collective name for marine macroalgae, which are the plants of the sea (see Chapter 2). The major pigments that give color to the algae include chlorophyll a, b, and c; β-carotene; phycocyanin; xanthophylls; and phycoerythrin. All these pigments are of great potential for applications in food, pharmaceuticals, and cosmetics. Brown seaweed is usually large, ranging from the giant kelp that can often be as long as 2-4 m, whereas red seaweed is usually smaller, generally ranging from a few centimeters to about a meter in length. Of the large number of species of seaweed found all over the world, a few species of red algae have been in use for at least a few centuries. The earliest record of use of seaweed dates back to 2700 BC in the compilation of “Chinese Herbs” by Emperor Shen Nung.1 Seaweed has been an important dietary component since, at least, fourth century in Japan and sixth century in China.2 In Korea also consumption of seaweed is a common practice. In these countries, red and brown seaweed powders are traditionally consumed as condiment agents in a variety of foods. Average algal consumption per person in Asia and Africa has been very low between 3 and 13 g.3 Hydroclathrus, Caulerpa, Eucheuma, Gracilaria, and Acanthohora spp. are used as green salad vegetable, whereas the coarser Gracilaria and Eucheuma spp. are pickled.4,5 In Asian countries, seaweed are directly used for several culinary purposes, whereas, in the west, such direct uses are limited; they are almost exclusively used for the phycocolloid industry for extraction of important food hydrocolloids including carrageenan, alginic acid, and agar.5-7 From time immemorial seaweed have also been used as manure in the coastal areas. This chapter discusses composition, nutritional value, and some functional properties of seaweed. Detailed functional properties of individual seaweed hydrocolloids will be covered in the subsequent chapter. Aspects such as ecological, morphological, and genetic aspects are not coming within the purview of these discussions.
