超声波辅助韧化改性甘薯淀粉的结构及理化特性

Effects of Ultrasound Assisted Annealing Modification on Structure and Physicochemical Properties of Sweet Potato Starch

为研究超声波辅助韧化对甘薯淀粉特性的影响,在其韧化不同阶段施加超声波,并对其表观直链淀粉含量、相对分子质量、支链淀粉链长分布、淀粉颗粒形态、结晶结构、糊化、流变、凝胶性质等进行表征。结果表明,在韧化中施加超声波对支链淀粉侧链分布和淀粉颗粒形态特征无显著影响;超声波辅助韧化在一定程度上改变了甘薯淀粉的结晶结构,韧化中间阶段施加超声波使其相对结晶度从31.98%减少至25.71%;与单独韧化相比,超声波辅助韧化使甘薯淀粉具有更高的回升值(1 220 cP)和更低的崩解值(1 594 cP),同时使甘薯淀粉凝胶的G″与G′值升高,大幅提高了甘薯淀粉凝胶的弹性和黏性;超声波辅助韧化使甘薯淀粉的凝胶硬度、胶黏性和咀嚼性增加。

In this study,the effects of ultrasound assisted annealing on the characteristics of sweet potato starch were investigated.The ultrasonic treatment had been involved at different stages of the annealing treatment and the physicochemical properties of modified sweet potato starch,such as apparent amylose content,relative molecular weight,amylopectin chain length distribution,starch particle morphology,crystal structure,gelatinization,rheology and gel properties were characterized.The results indicated that ultrasonic treatment had no significant effect on the amylopectin chain length distribution and the morphological characteristics of starch granules during the annealing process;annealing-ultrasonic dual modification made the crystalline structure of sweet potato starch changed to a certain extent,and the ultrasonic treatment in the intermediate stage reduced its relative crystallinity to the greatest extent(from 31.98% to 25.71%).Compared with annealing,ultrasound assisted annealing made sweet potato starch had higher setback viscosity(1 220 cP) and lower breakdown viscosity(1 594 cP).Ultrasound assisted annealing modification increased the G″ and G′ values of starch gel,greatly improving the elasticity and viscosity of starch gel.Ultrasound assisted annealing modification increased the gel hardness,gumminess and chewiness of sweet potato starch.