Abstract The effects of the combination of freeze-thawing and enzymatic hydrolysis on the microstructure and physicochemical properties of porous corn starch were investigated. The combined treatment produced more pores in each starch granule than either individual treatment, as revealed by scanning electron microcopy (SEM). Consequently, this porous starch treated by combined treatment increased adsorptive capacity for water and oil, swelling power and solubility, that the openings and cavities induced in starch granules by freeze-thawing enhanced the susceptibility of starch to enzymatic digestion. Compared to native starch, the particle sizes decreased, while the crystallinity and gelatinization enthalpy of starch processed by the combined treatment increased, as determined by Fourier Transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses. The values of particle size, crystallinity and gelatinization enthalpy for starch processed with the combined treatment were intermediate to those of starch processed with either freeze-thawing or enzymatic hydrolysis. While the particle size was higher than that of native after freeze-thawing but the obviously decreased after enzymatic hydrolysis. The crystallinity and enthalpy of starch decreased from 15.51 to 4.19 J/g to 14.65% and 4.12J/g after freeze-thawing but increased to 16.09% and 4.74J/g after enzymatic hydrolysis. Enzymatic hydrolysis causes opposite and more severe changes to the starch granule compared with freeze-thawing. The variation in pasting viscosities by combined treated revealed the water was easy to enter starch by the pores on the surface. In brief, the combined treatment is an attractive alternative for obtaining porous corn starch.

中文翻译：

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冻融结合酶解对多孔玉米淀粉微观结构和理化性质的影响

摘要 研究了冻融结合酶解对多孔玉米淀粉微观结构和理化性质的影响。扫描电子显微镜 (SEM) 显示，联合处理在每个淀粉颗粒中产生的孔比任何一种单独处理都多。因此，这种经过联合处理的多孔淀粉增加了对水和油的吸附能力、溶胀力和溶解度，冻融导致淀粉颗粒中的开口和空腔增强了淀粉对酶消化的敏感性。与天然淀粉相比，通过傅里叶变换红外光谱（FT-IR）测定，组合处理后淀粉的粒径减小，而结晶度和糊化焓增加，X 射线衍射 (XRD) 和差示扫描量热法 (DSC) 分析。联合处理加工的淀粉的粒径、结晶度和糊化焓值介于冻融或酶水解加工的淀粉之间。虽然冻融后粒径大于天然粒径，但酶解后粒径明显减小。淀粉的结晶度和热函在冻融后由15.51-4.19J/g降低到14.65%和4.12J/g，酶解后提高到16.09%和4.74J/g。与冻融相比，酶促水解会导致淀粉颗粒发生相反且更严重的变化。复合处理后糊化粘度的变化表明，水很容易通过表面的孔隙进入淀粉中。