Abstract:The effects of a hydrolysate of whey protein isolate (WPI) on the antioxidant capacity and preservation of grass carp surimi stored at 4°C were investigated. Changes in the carbonyl content, thiobarbituric acid-reactive substances (TBARS) value, the total number of bacterial colonies, total volatile basic nitrogen (TVB-N) value, trimethylamine (TMA) value, and K value of grass carp surimi were measured at different storage times (days 0, 1, 3, 5, 7, and 9), and the correlation between the indices was studied. Experimental samples were divided into five groups: group 1: control group; groups 2 to 4: addition of 2%, 4%, and 6% WPI hydrolysate, respectively; group 5: addition of 0.02% butylated hydroxyanisole (BHA). The results showed that protein and lipid oxidation in surimi were significantly inhibited with increasing amounts of added WPI hydrolysate (p<0.05), and the preservation effect was markedly improved. The most significant effect was observed in surimi with the addition of 6.0% WPI hydrolysate; during the nine-day storage period, the carbonyl content, TBARS value, TVB-N value, and K value were decreased by 1.54 nmoL/mg protein, 0.21 mg/kg, 5.84?10-2 mg/g and 11.7%, respectively, compared with those of control; the grass carp surimi was still in the second grade of freshness after nine days of storage. Additionally, all indices had a significant positive correlation (p<0.05). Therefore, WPI hydrolysate has a strong effect on antioxidant capacity and preservation, and can be considered for use as a natural preservative for surimi products.
