Biochemical and functional properties of herring (Clupea harengus), byproduct hydrolysates

The functional, nutritional, and antioxidative properties of hydrolyzed herring and herring byproducts (head and gonad) were evaluated. All freeze-dried herring fish protein hydrolysate (FPH) powders were light yellow and contained 77% to 87% protein. The degree of hydrolysis was 18.3%, 13%, 13%, and 10.1%, respectively, for head, whole fish, body, and gonad after 75 min digestion. All FPH powders had desirable essential amino acid profiles and mineral contents. The emulsifying capacity and stability of all FPH powders were lower than those of egg albumin and soy protein; the fat adsorption was comparable to that of egg albumin. The antioxidative activity of whole herring FPH was highest, followed by that of body, gonad, and head.