Improving gelling properties of fish gelatin by γ‐polyglutamic acid with four different molecular weights

Abstract

SummaryThis work investigated gelling properties and structural characteristics of fish gelatin (FG) modified by four different molecular weights of γ‐polyglutamic acid (γ‐PGA) with 700, 1000, 2000 and 3000 kDa, respectively. Gelation‐melting transition temperature and gel strength increased with the increase of molecular weight in γ‐PGA. Especially, γ‐PGA in 3000 kDa made gel strength, gelation and melting temperatures reaching to 628.08 g (P < 0.05), 22.30 °C and 30.17 °C (P < 0.05), respectively. Non‐covalent interactions existed in FG and γ‐PGA. Such as, new hydrogen bonds were generated between them. Moreover, γ‐PGA with increased molecular weight enhanced three‐stranded helical structure and microscopic meshwork of FG. Finally, a schematic model was described to illustrate the interaction between FG and γ‐PGA in different molecular weights. On the whole, γ‐PGA with high molecular weight significantly improved gelling properties of FG, and could be a potential modifier of FG in the future.