The effect of enzymatic hydrolysis on amino acids composition of Persian sturgeon (Acipenser persicus) viscera protein hydrolysate

Protein hydrolysate was prepared from visceral waste proteins of Persian sturgeon (Acipenser persicus), an Iranian major sturgeon. Hydrolysis was performed at 55 ° C, 205 min, pH 8.5 by 0.1 AU/g protein E/S Alcalase 2.4L. Protein content for hydrolysate was 65.82%, and lipid content was 0.18%. The highest degree of hydrolysis was observed in conditions of 55°C after 205 min. (46.13%) (P<0.05). The results showed that the amino acid profiles of the Persian sturgeon viscera hydrolysates were generally higher in essential amino acid profiles compared with the suggested pattern of requirement by FAO/WHO for adult humans and could fulfill this requirement. Key word: Enzymatic hydrolysis, Sturgeon Protein hydrolysate, amino acid profile, degree of hydrolysis Introduction Every year over 132 million tons of fish are harvested, of which 29.5% is converted into fish meal (FAO, 2006). Possibly more than 50% of the remaining fish tissue is considered to be non-edible waste material. With dramatically increasing world population and a world catch of fish more than 100 million tons/year, there is obviously an increased need utilize our sea resources with more intelligence and foresight. By applying enzyme technology for protein recovery in fish processing, it may be possible to produce a broad spectrum of food ingredients or industrial products for a wide range of applications. This would utilize both fisheries byproducts and secondary raw materials and, in addition, underutilized species that would otherwise be discarded. Fish viscera are one of the most important byproducts, which rich source of protein and polyunsaturated lipids with low storage stability if not frozen or otherwise preserved. Enzymatic modification of proteins using selected proteolytic enzyme preparations to cleave specific peptide bonds is widely used in the food industry (Kristinsson and Rasco, 2000a).Generally, Alcalase 2.4 L-assisted reactions have been repeatedly favoured for fish hydrolysis due to the high degree of hydrolysis that can be achieved in a relatively short time under moderate pH conditions compared to neutral or acidic enzymes (Hoyle and Merritt, 1994; Shahidi et al., 1995; Kristinsson and Rasco, 2000a, b; Bhaskar et al., 2008). Hydrolyzing protein can also improve intestinal absorption (Kristinsson and Rasco, 2000a), and be used as a source of peptides, such as peptone, for ingredient in microbial growth media (Gildberg et al., 1989). Persian sturgeon is one of the most important sturgeon fishes on the Iranian coast of the Caspian Sea for both meat and caviar production. Sturgeon processing waste is usually discarded without any recovery except for the swim bladder. Sturgeon viscera could be a rich source of protein which can be used as