Gallic acid and heat moisture treatment improve pasting, rheological, and microstructure properties of Chinese yam starch-chitosan gels: A comparative study

Nowadays，It is difficult for the polysaccharide-starch system to meet demand of practical production owing to the poor gel properties. Therefore, aiming to further improve the practical application of polysaccharide-starch gel, the effects of gallic acid (GA) and heat moisture treatment (HMT) on the gel properties and microstructure of yam starch/chitosan (YS/CS) composite gels were investigated. Swell power (SP) results showed that GA and HMT treatment respectively reduced the SP of YS gel by 3.24 g/g and 6.03 g/g, given that GA and HMT decrease the rheology of the water phase inhibiting the entry of water into the swollen starch. In the pasting process, HMT reduced pasting viscosity of the HMT/YS system because only little amylose was leached in the medium for elevating its viscosity after HMT. The rheological properties suggested that high temperature treatment of HMT facilitated the disruption and disintegration of starch granules resulting dynamic modulus had a decline trend. The elastic properties of GA/YS gels were enhanced with the addition of GA, which could be supported by the thicken lamellar observed in its microstructure. In general, GA and HMT effectively alter the gel properties of YS/CS gel system, and facilitate its practical application in food industry.