Production and characteristics of protein hydrolysates from capelin (Mallotus villosus)

Protein hydrolysates were prepared from male and spent capelin (Mallotus villosus) using commercially available Alcalase, Neutrase and papain. Short-time autolysis of proteins by endogenous enzymes in fish viscera was also investigated and compared to procedures of accelerated enzymatic hydrolysis. While protein recovery varied from 51.6 to 70.6% for commercial enzymes, a yield of 22.9% was obtained for autolyzed products. All methods of preparation afforded products containing about 71–78% proteins after dehydration. Alcalase served best for preparation of capelin protein hydrolysates (CPH). Thus, products of Alcalase-assisted hydrolysis of capelin proteins were further assessed for their nutritional and functional characteristics. The amino acid composition of CPH was similar to that of the starting capelin, except for methionine and tryptophan which were present in smaller amounts. The products had excellent solubility (≥84%) over a pH range of 2–11. Incorporation of CPH (up to 3%) in meat model systems resulted in an increase of 4% in cooking yield and inhibition of oxidation (determined by the 2-thiobarbituric acid test) by 17.7–60.4%.