Biochemical and Functional Properties of Enzymic Protein Hydrolysate from Croaker (Otolithus ruber)

摘要

Fish protein hydrolysate (FPH) was prepared from minced muscle of croaker (Otolithus ruber) using a bacterial proteolytic enzyme Alkalase. Protein hydrolysis was carried out at 55 deg C, pH 8.5 with 0.5% and 0.8% enzyme concentration for the reactiontime of 60, 120, 210 min respectively. The soluble portion separated after incubation was heated at 95 deg C for 10 min, cooled and freeze dried. The final product possessing a creamy white colour contained 72.25% protein and 2.60% fat. At 39.87% degreeof hydrolysis, croaker hydrolysate presented good functional properties as compared to protein hydrolysate with 55.22%, 68.73%, 71.14%, 95.88% degree of hydrolysis (DH). The FPH with 39.87% DH had 88.92% solubility, 183% foamability and more than 10 secfoam stability, 13.44 m~2/gm emulsifying activity, 2.9 mL water/ gm of protein water absorption and excellent wettability. Browning and increase in bitterness of the product was observed when stored under air and nitrogen for 60 days. The peroxide valueof the final product was insignificant and no change occurred in its value during storage. Organoleptically, nitrogen packed samples had better score than the air packed sample, however, both the samples had shelf life of more than 60 days.