Chemical and biophysical properties of gelatins extracted from alkali-pretreated skin of cuttlefish (Sepia officinalis) using pepsin

Abstract Gelatins from alkali-pretreated skin of cuttlefish ( Sepia officinalis ) were extracted with different concentrations of pepsin at pH 2.0 and characterized. The increase of enzyme concentration increased the yield of gelatin extraction. The yields of gelatins G5, G10 and G15, extracted, respectively, with 5, 10, and 15 U of pepsin/g of alkali-treated skin of cuttlefish, were 6.59%, 7.69% and 9.22%, respectively, while in the absence of pepsin (G0) the yield was only 2.68%. Nevertheless, the extraction of gelatin from alkali-pretreated skin of cuttlefish with pepsin at pH 2.0 affected the molecular weight, biophysical and functional properties of resulting gelatins. Gelatin extracted without pepsin showed the higher gel strength, and transition, gelling and melting temperatures, which are slightly higher than G5. All of these values decreased with increasing enzyme concentration. In addition, foam expansion (FE) was affected by enzymatic treatment, and the values decreased as pepsin increased. Nevertheless, the partially hydrolyzed gelatins showed the same emulsifying properties.