Effects of Microwave Treatment on the Structure and Physicochemical Properties of Three Kinds of Starches

To investigate the effects of microwave treatment on the structural characteristics and physicochemical properties of mung bean starch, pea starch and indica starch, three kinds of starch before and after microwave treatment were used as raw materials to explore the effects of microwave treatment on amylose content, particle morphology, polarization characteristics, crystallization structure, short-range order, thermal properties, gelatinization properties and retrogradation of three kinds of starch. The results showed that after microwave treatment, the amylose of mung bean starch, pea starch and indica starch increased from 36.78%, 40.29%, 15.96% to 45.49%, 44.17%, 27.78%, respectively. After microwave treatment, the granules of the three kinds of starch showed different degrees of cracks and damage, and more than half of the polarized cross disappeared. The crystal form and functional groups of mung bean starch, pea starch and indica starch after microwave treatment did not change, but the relative crystallinity of starch decreased by 7.03%, 4.94% and 5.32%, respectively. After microwave treatment, the peak viscosity, valley viscosity, retrogradation value and gelatinization enthalpy of the three kinds of starch decreased significantly (P<0.05). The retrogradation rate of mung bean starch and pea starch after microwave treatment was faster and more stable than that of indica starch. The above results showed that microwave treatment had a significant effect on the particle structure and physicochemical properties of the three starches.