Rheological properties and structure modification in liquid and gel of tilapia skin gelatin by the addition of low acyl gellan - Yang Lab

Fish gelatin (FG) was modified by low acyl gellan (Ge) to produce a replacer for pork gelatin (PG). Increasing mixing ratio of Ge:FG (w/w) modified rheological properties and structure of FG progressively. The largest of FG-Ge complex coacervates (1775 ± 593 nm) formed at Ge:FG (w/w) of 7.5:92.5, driven by electrostatic interaction between FG and Ge. However, the network density was reduced by the formation of large complex coacervates (fractal dimension, df 2.45 ± 0.01 in FG-Ge vs. 2.48 ± 0.00 in FG). The non-interacting FG reassociated to a greater extent into triple helix (helix/coil ratio, 3.10 ± 0.93 in FG-Ge vs. 0.58 ± 0.07 in FG), therefore increased the rigidity of the gel. The mixed gel was stronger and more stable, with lower compliances (J0, Jm1) and a higher melting temperature (Tm) than FG. The mixed gel at a Ge:FG (w/w) of 1:99 had similar rheological properties to PG. A schematic model was proposed to illustrate the progressive modification of FG by Ge.