The annual production of seaweed in the world is 6.5 million tons. This marine resource is mainly developed as a food additive and marine vegetable. In some countries in Asia, seaweed is eaten as marine vegetables, of which Japan is the main consumer country, and each person averages 1.6 kg dry weight per year.
In Europe, algae. In particular, brown seaweeds are generally used for the production of additives or coarse powders for animal nutrition components. In most cases, seaweeds as human and animal foods are due to the functional properties of minerals or polysaccharides contained in seaweed. However, the proteins contained in seaweed are rarely developed.
First, the protein content of seaweed Because of different species, the protein content of seaweed is also different. The contents of green algae and red algae are generally higher than those of brown algae, and most of the brown algae used for industrialization have a protein content of less than 15% (dry weight), and some of algae have a protein content of between 10% and 26% ( Dry weight). Algae with higher protein content are red algae, and the protein content of some species of red algae can reach 47%, which is higher than the protein content of soybean.
The protein content of algae is also affected by the seasons, generally with high protein content in the late winter and spring and low protein content in summer.
Second, the amino acid composition People studied the amino acid composition of seaweed, and other foods such as eggs or soybean amino acid composition were compared. Most of the algae, aspartic acid and glutamic acid account for most of the content, such as brown seaweed. These two amino acids accounted for 22% and 44% of the total amino acids respectively. The two amino acids in green algae accounted for the total amino acids, respectively. 26% and 32%, while the content of glutamic acid and aspartic acid in red algae is relatively low. In some red algae, containing essential amino acids and leucine, valine and methionine, the average level of these amino acids close to the level of ovalbumin, in addition, isoleucine and threonine The content is close to that of legume protein.
Third, the potential use of algae protein Because red algae has a high content of protein and its amino acid composition, so the red algae as a potential source of food protein has attracted attention. In Europe, there is a new type of functional food being developed that uses red algae, particularly protein-rich ones, to increase human nutrition. In addition, some phycoerythrins contained in red algae have been applied biotechnologically. The main problem of using phycoerythrin as a food pigment is its relative stability to heat and pH changes, but it has been obtained The physical conditions for improving the stability of phycoerythrin, in addition, there are also other methods of enzyme treatment can also improve the stability of phycoerythrin, therefore, there is still a certain potential as a food pigment.
The use of protein-rich seaweed as a feed for fish is another use of seaweed. Feed containing seaweed can increase the body weight of aquatic animals and increase the accumulation of triglyceride and protein in muscles. In addition, seaweed can also increase the use of fish. Disease resistance.
Therefore, seaweed is a supplementary source of food proteins for human and animal nutrition, and their amino acid content is also satisfactory. However, there are few studies on whether algae protein can be well digested in humans. Today, algae are degraded by enzymes. Fiber can increase the digestion of proteins, thereby increasing the nutritional value of algae proteins. In addition, red algae is a potential source of food additives and special food pigments, which presents new challenges for future research.