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Functional and antioxidative properties of protein hydrolysates from Cape hake by-products prepared by three different methodologies


Correspondence to: Carla Pires, INRB, I.P/L-IPIMAR, Unidade de Valorização dos Produtos da Pesca e Aquicultura (U-VPPA), 1449-006 Lisboa, Portugal. E-mail:


BACKGROUND: The production of fish protein hydrolysates (FPH) is a convenient technology for upgrading fish by-products. The aim of this work was to study three different methods of FPH preparation from Cape hake by-products to improve yield and quality. Functional and antioxidative properties of all FPHs were determined.

RESULTS: The protein content of hake FPH was in the range 807–860 g kg−1 and the degree of hydrolysis was between 19% and 22%. The maximum yield (71.9%) was achieved by methodology B but the hydrolysate was darker. The peptide profile of all FPHs was very similar. FPH prepared by methodology C had significantly higher emulsifying activity index and hydrolysate prepared by methodology B had the highest foaming capacity. The solubility of FPH was in the range 71–76% and increased the water-holding capacity of minced fish by about 9%. The fractionation of FPH obtained by methodologies A and B allowed concentrating peptides with higher radical scavenging activity and reducing power.

CONCLUSION: The properties of the FPH prepared indicated that they can be used in food systems as natural additives, particularly to improve their water-holding capacity. © 2012 Society of Chemical Industry