Autolysis-assisted production of fish protein hydrolysates with antioxidant properties from Pacific hake (Merluccius productus)

Fish protein hydrolysates (FPH) with antioxidative properties were prepared using Pacific hake fish with high endogenous proteolytic activity from Kudoa paniformis parasitic infection. Infection level of similar to 10(7) K paniformis spores/g fish mince or higher yielded FPH with high antioxidant potential by autolysis and/or Validase(R) BNP or Flavourzyme(R) 500L. Autolyzing fish mince containing 30 x 106 spores/g for 1 h at 52 degrees C and pH 5.50 produced FPH (named E-1h) with Trolox equivalent antioxidant capacity (TEAC) in the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) radical assay of 262 +/- 2 mu mol/g and oxygen radical absorbing capacity (ORAC) of 225 +/- 17 mu mol Trolox equivalents/g freeze-dried sample. E-1h FPH also exhibited a marked concentration-dependent scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radical. Antioxidant activity of E-1h FPH was higher (p < 0.05) than BHA and alpha-tocopherol in a linoleic acid peroxidation system over prolonged storage (similar to 162 h). Antioxidative FPH from Pacific hake may be useful ingredients in food and nutraceutical applications. (C) 2007 Elsevier Ltd. All rights reserved.