Effects of Freeze-thaw Cycles on Physicochemical Properties of Castanea henryi Starch

Objective:The effects of freeze-thaw cycles(FTC,with-20℃/22 h,25℃/2 h as a cycle)on the physicochemical properties of Castanea henryi starch were studied in this paper.The aim was to provide the theoretical references for the modification of Castanea henryi starch and the development of products. Methods:The basic compositions were compared between native and 3,7 and 10 FTC starch;proportion of crystalline region was analyzed by fourier transform infrared spectroscopy(FTIR);particle size distribution range was determined by laser particle size analyzer;retrogradation was observed by the changes of syneresis rate;pasting properties of starch was analyzed by rapid viscosity analyzer(RVA);shear-thinning,storage modulus and loss modulus were analyzed by rheometer;texture properties of starch gels were tested by texture analyzer(TPA). Result:Compared with native starch,Castanea henryi FTC starch caused a decrease in protein,fat and amylose and an increase in damaged starch. Proportion of crystalline region and particle size distribution range of 3 and 7 FTC starch were gradually reduced,but 10 FTC starch recovered slightly. The native and FTC starch paste were both retrogradated within 70 h,and the syneresis rates of FTC starch pastes were reduced. Pasting temperature of FTC starch decreased,while peaking viscosity and setback viscosity increased. Storage modulus of 3 and 7 FTC starch were lower than the native one,but for 10 FTC starch it was slightly higher with an increase of shear stress. The hardness of FTC starch gels was reduced,while elastic and adhesiveness increased. Conclusion:The effects of FTC on physicochemical properties of Castanea henryi starch were significant. The results of this study could provide a theoretical reference for the freeze-thaw mechanism of Castanea henryi starch-based food.