Effect of chitosan and hydroxypropyl starch complex polysaccharide on the physico-chemical properties of Tilapia fish (Oreochromis mossambicus) gel

The compound polysaccharide composed of chitosan and hydroxypropyl starch was aimed in this study to be used as a novel treatment to improve the quality of Tilapia fish surimi. Surimi gel properties, retention of oil, rate of water loss, colour changes, changes in protein content and gas composition were analysed. Compared with the control group, with the increase of hydroxypropyl starch content, the rate of water loss in all the groups (chitosan and hydroxypropyl starch) was improved, and 1.5% chitosan-treated samples showed significantly lower water losses. The protein content tended to increase at the beginning and then decrease. The whiteness index of surimi in both groups was significantly improved. The addition of 1.0% hydroxypropyl starch showed the highest oil retention in all treated groups (1.0% chitosan treated sample showed oil retention of 0.77 mL/g, while 1.5% chitosan treated samples showed maximum oil retention of 0.7 mL/g). Gas chromatography-mass spectroscopy (GC-MS) analysis detected two identical volatile organic compounds (VOCs) in both the control and compound polysaccharide groups. These results indicate that using complex polysaccharides can significantly improve the quality of fish surimi and, therefore, can be used as a practical basis for industries to improve freshwater fish surimi’s gel properties.