Gelation kinetics and characterization of enzymatically enhanced fish scale gelatin–pectin coacervate

BACKGROUND Protein – polysaccharide complex coacervations have been considered extensively for the development of functional foods. The main problem of the complex coacervates is high unstable under different conditions and that cross-linking is necessary to stabilize them. In this study, the effects of pectin at different concentrations on the gel and structural properties of fish scales gelatin (FSG) – high methoxyl citrus pectin (HMP) coacervate enhanced by microbial-transglutanminase (MTGase) were studied. RESULTS The gelation rates and gel strength of the MTGase enhanced FSG – HMP coacervate gels decreased with increasing HMP concentration. However, the enhanced coacervate gels exhibited better thermal behavior and mechanical properties compared with the original gels. And TG-P8 exhibited the highest melting point (27.15±0.12 oC), gelation point (15.65±0.01 oC) and stress (15.36±0.48 kPa). Particle size distribution, fluorescence emission, and UV absorbance spectra indicated that MTGase and HMP could make FSG form large aggregates. Moreover, confocal laser scanning microscopy of treated coacervate gels showed a continuous protein phase at low HMP concentrations. CONCLUSION FSG and HMP could form soluble coacervate, and MTGase could improve the thermal and mechanical properties of coacervate gels.