Rheological properties of fish (Sparus aurata) skin gelatin modified by agricultural wastes extracts

In this study, fish skin gelatin (FG) obtained from sea bream (Sparus aurata) was evaluated as an alternative to mammalian gelatin. Improvement in rheological properties of FG was attempted with addition of grape pomace (GP), pomegranate peel (PP), and green tea (GT) extracts, all of which are agricultural wastes rich in phenolic components. These additives were added at ratios of 20%, 13.3%, 10%, and 6.7% to determine the best formulation. Melting and gelling temperatures, kgel, gel strength, and tmodel values of samples were measured. 20% GP added fish gelatin (OG) had optimum rheological properties. Melting temperatures of BG, OG, and FG were 31.64 +/- 0.28, 33.80 +/- 0.54, 25.78 +/- 0.24 degrees C, respectively. The addition of GP caused a 14% increase in Tg by increasing the intermolecular interactions of FG. GP is important in that it provides functional properties and structural improvement of FG, making it an alternative to BG and facilitating its use in confectionery industry.