Effect Of Ball Milling And Heat-Moisture Treatment On Structure And Physicochemical Properties Of Starch

The study of ball milling(BM) and heat-moisture treatment(HMT) on structure and physicochemical properties of different sources starch. Firstly, we study the effect of ball milling treatment on structure and physicochemical properties of different conpenents of wheat starch. The starch with vary damage contents was modified by HMT and then the physicochemical properties of thoese modified starch were studied. Finally, the influence of BM-HMT treatment on structure and physicochemical properties of starch from other plant sources of starch.The different components of wheat starch were damaged by BM and the structure and physicochemical properties were studied. Results showed that starch granules were damaged more easily after degreasing, and the amylose content had negative correlated with the damaged degree of particles. The lower of lipid and amylose content, the greater the degree of crystallinity decreased after the ball mill. The contents of DS% significantly increased with lipids content decreased at the same time of ball milling, which had negative correlated with the amylose contents. Swelling power was inhibited by lipids and the lower the amylose content of starch, the faster increasing of the solubility and swelling power, The starch peak viscosity, setback, peak time and peak temperature were decreased significantly with degreasing, the higher the amylose content, the lower the peak viscosity. Results of DSC showed that gelatinization temperature range of four kinds of starch remained unchanged after degreasing, and the FT-IR characteristic peak intensity of defatted wheat starch weakened with the increase of ball milling time after degreasing. The higher the amylose content was, the stronger the peak intensity was at the same time of BM.The mechanical damaged starch was modified by HMT. Results showed that damaged starch granules began to gather with each other, defatted starch and low amylose content were more conducive to integration after HMT. X-ray results indicated that the different of amylose content had no obvious effect on the crystallinity of HMT starch, and the content of lipids had a great influence on the crystallization of HMT starch. The DS% content was reduced after HMT, and amylose content had effect on HMT damage starch content while lipid content had no obvious effect. The solubility and swelling power of damaged starch were decreased after HMT, and the viscosity of RVA curve was also decreased after HMT. DSC results showed that the gelatinization temperature of modified starch increased after HMT, and two gelatinization peaks were appeared; The gelatinization enthalpy was decreased with the increase of DS%, and the molecular structure of starch was changed after HMT according to FT-IR.Four different sources of starch(MS, PS, CS and WCS) were treated by BM and BM-HMT methods respectively, and their physicochemical properties were studied. According to SEM, damaged degree of starch granules surface had positive correlation with amylose content, and starch granules were conducive to integration after HMT. X-ray results showed that The crystallization of MS was conversed from type B to A after BM-HMT and the same phenomenon was occurred about MS-BM-1h-HMT and PS-BM-1h-HMT; The crystallinity was decreased after BM, while HMT could significantly improve the crystallinity; DS% had negative correlation with the amylose content and positive correlation with the degree of starch granules crushing, and DS% was significantly decreased after HMT; The solubility and swelling potential of four starch increased after BM, then decreased after HMT modification; DSC results showed that the value of To and ΔH of the four original starch had negative correlation with amylose content and To and ΔH value was significantly reduced after BM. However, the thermal stability of higher damaged starch could be improved by HMT; FT-IR results showed of starch strengthened with the increase of ball milling time except for corn starch and HTM could weaken the infrared spectrum characteristic peak intensity of damaged starch.Eight kinds of starch were modified by BM-HMT and the rheological properties were studied. Results showed that gel formation temperature of different starch decreased after BM treatment, then increased significantly by HMT treatment. HMT could improve the anti-deformation ability of starch so that the gel strength of damaged starch increased and it was not easy to deformation under the action of external force.