Preparation and use of freshwater fish, rohu (Labeo rohita) protein dispersion in shelf-life extension of the fish steaks

A process to enhance shelf-life of freshwater fish, rohu, on ice using combination treatment of coating the fish steaks with gel dispersion from the same fish and low-dose gamma irradiation is described. Washed pieces of freshwater fish, rohu were converted into gel by dilute acetic acid treatment. The gel was homogenized in water to a dispersion having 29 g/L protein, apparent viscosity of 1.0 Pa s and pH 3.5. Coating of fresh rohu steaks by dipping in the dispersion for 1 h or gamma irradiation at 1 kGy gave a shelf-life of 32 days in ice, in comparison to 20 days for the untreated steaks. Irradiation at 1 kGy of the dispersion-coated steaks enhanced their shelf-life to 42 days. Bleaching of the pink colour of the steaks by the treatment was prevented when one of either butylated hydroxy anisole or ascorbic acid was incorporated at 5 g/kg (w/v) in the dispersion. (C) 2003 Swiss Society of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.