Characteristics and functional properties of gelatin and gelatin hydrolysate from bigeye snapper (Priacanthus tayenus) bone

Abstract

Bigeye snapper bone, a by-product from the surimi industry, was a starting material to prepare gelatin through hot water extraction (HG) and retort extraction (RG). Yields of HG and RG were 0.35 and 0.90% (based on wet weight), respectively. It was high in protein content (72.15-75.36%). Gelatins from both methods showed significant differences in the quantity of chemical compositions (P≤0.05). The HG showed greater gel strength (384 g) and viscoelastic properties than the RG (P≤0.05). Both HG and RG were then hydrolyzed by protease (papain) with a degree of hydrolysis of 43.29% and 37.22%, respectively. The functional properties and antioxidant capacities of both gelatin hydrolysates were also investigated. The HG hydrolysate (HGH) showed higher foam expansion (1.33-14.67%), but a lower emulsifying stability index (33.5-5.33 mins) than those of RG hydrolysate (RGH) (0.67-8.00% and 76.8-1.0 min, respectively). Antioxidant capacities showed that both HGH and RGH are good sources of functional ingredients in foods.