Seaweed proteins

Scientific reports dealing with functional effects of seaweed proteins, peptides, amino acids, polysaccharides, phytochemicals, lipids, and minerals greatly endorse the efforts toward development of "health foods" using seaweeds. Table 1.1 provides some seaweed species studied and recognized for their richness in functionally important molecular groups. Evaluation of functional properties requires a clear idea about their biochemical composition, and it provides a platform to have an inspiration to decide on the molecules responsible for different biological activities. 

However, aspartic and glutamic acid that exhibit interesting properties in flavor development are less in red seaweed compared to that in brown seaweed. In addition, the blue-green alga, Spirulina, is well known for its very high protein content which is close to 70% of the dry matter. The in vivo digestibility of seaweed proteins is not well documented. However, the extractabUity and the in vitro digestibility of seaweed protein attain more than 80% irrespective of the species (Flem-ence, 1999). 

Fleurence, J. (1999). Seaweed proteins Biochemical, nutritional aspects and potential uses. 

Seaweed Proteins and Amino Acids as Medicinal Food... 

In comparison to the standard protein, seaweed proteins (as well as other plant proteins) are not full-valued proteins because of low amoimts of some amino acids. Nevertheless, the presence of all EAAs in the considerable quantities indicates that seaweed proteins are nutritionally superior to the terrestrial plant proteins (Qasim, 1991). In Tables 24.3 and 24.4, there are presented protein contents of some seaweed demonstrating their variability. 

In vitro protein digestibility of seaweed proteins is influenced by the species, seasonal period, and content of antinutritional factors such as phenolic and polysaccharides (Fleurence, 1999a Mabeau and Heurence, 1993). Activity of proteolytic enzymes may be reduced due to the reaction of amino acids with oxidized phenolic compound (Wong and Cheimg, 2001). Differences between the prediction of protein quality (based on amino acid content/amino acid requirement ratios) and the actual protein quality (based on the performance in living organisms) seem to be a reason of variations in the utilization of the amino acids comprised in different proteins. 

Biochemical and nutritional aspects of seaweed proteins have been reported. Enzymatic degradation of algal fibers could be attempted to improve protein digestibility (Fleurence, 1999) and also to prepare bioactive peptides. A great deal of interest has been developed nowadays to isolate antihypertensive bioactive peptides, which act as angiotensin-con-verting enzyme (ACE) inhibitors because of their numerous health beneficial effects (Wijesekara and Kim, 2010). 

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