乙醇-热处理制备冷水溶胀小麦淀粉及其结构和功能特性的研究

Structure and Functional Properties of Cold Water Swelling Wheat Starch by Ethanol-Heat Treatment

将天然小麦淀粉分散到不同浓度的乙醇溶液(0、10%、20%、30%、40%、50%)中,在80℃下加热处理30 min制备冷水溶胀小麦淀粉,研究了不同乙醇浓度下小麦淀粉的晶体结构、功能特性(持水性、持油性、糊化特性、凝胶强度)及微观形态的变化。结果表明,0~40%处理组X-射线衍射图谱中天然小麦淀粉的A-型晶体结构完全消失,50%处理组呈现有部分天然小麦淀粉的衍射峰;与傅里叶变换红外光谱的结论一致。与此同时,当乙醇浓度从10%增加到40%时,处理组样品持水性、持油性、凝胶强度显著提高(P<0.05),乙醇浓度进一步增加至50%时,持水性和持油性显著下降(P<0.05)。此外,扫描电镜表明0~40%处理组颗粒表面裂缝数随着乙醇浓度的升高增多,而50%处理组仅表面出现褶皱无裂缝。综合考虑,选取40%乙醇浓度处理小麦淀粉制备冷水溶胀淀粉的效果最好。

The native wheat starch was dispersed into ethanol solutions of different concentrations(0, 10%, 20%, 30%,40%, 50%) and heated at 80 ℃ for 30 min to prepare cold water swelling wheat starch. The crystal structure, functional properties(water holding capacity, oil holding capacity, gelatinization property, gel strength) and micromorphology of wheat starch by different ethanol concentration treatments were studied. The results showed that, the A-type crystal structure of natural wheat starch of X-ray diffraction pattern in 0~40% treatment group completely disappeared, 50%treatment group showed some diffraction peaks of natural wheat starch. This was consistent with the result of Fourier transform infrared spectrum. Meanwhile, as the concentration of ethanol increased from 10% to 40%, the water and oil holding capacity and gel strength of starch significantly increased(P<0.05), however, with the increasing of ethanol concentration to 50%, the water and oil holding capacity of starch significantly decreased(P<0.05). Furthermore, scanning electron microscopy showed that the number of cracks on the surface of 0~40% particles increased with the increasing of ethanol concentration, while 50% showed only wrinkles and no cracks on the surface. In conclusion, 40% ethanol concentration was the best method to prepare cold water swelling starch from wheat starch.