不同化学方法制备的抗性淀粉理化性质及表征研究

Physical and Chemical Properties and Characterization of Resistant Starch Prepared by Different Chemical Methods

本文以红薯淀粉为原料,采用三种化学方法制备抗性淀粉。研究酶解性、持水性、透明度、溶解度、膨润度和冻融性等理化指标,并采用扫描电镜、红外光谱进行表征分析。结果表明,淀粉被α-淀粉酶解4 h释放0.79 g还原糖,酯化淀粉、醚化淀粉和交联淀粉释放0.18、0.21和0.33 g还原糖,证明抗性淀粉具有较强抗酶解性;三种抗性淀粉持水性高于淀粉,醚化淀粉持水性最高;酯化淀粉比原淀粉透光率、溶解度和膨润度提高103.05%、14.56%、13.94%,醚化淀粉提高334.11%、356.97%、124.73%,交联淀粉却降低54.54%、67.75%、31.51%;三种抗性淀粉冻融性优于原淀粉,醚化淀粉冻融性最佳;原淀粉颗粒表面光滑,呈规律圆形,酯化淀粉和交联淀粉内外结构被破坏,失去原有形貌,醚化淀粉仍保持原淀粉原有形貌;红外图谱证明酯化淀粉引入乙酰基基团,醚化淀粉引入羧甲基基团,磷酸交联淀粉引入磷酸基团。

The resistant starch was prepared from sweet potato starch by three chemical methods.Physical and chemical indexes such as enzymatic hydrolysis,water retention,transparency,solubility,swelling and freezing-thawing property were studied.The results showed that starch released 0.79 g reducing sugar after enzymatic hydrolysis for 4 h,while esterified starch,etherified starch and cross-linked starch released 0.18,0.21 and 0.33 g reducing sugar,indicating that resistant starch had strong enzymatic hydrolysis resistance.The water holding capacity of the three kinds of resistant starch was higher than that of starch,and the water holding capacity of etherified starch was the highest.The transmittance,solubility and swelling of esterified starch increased by 103.05%,14.56%and 13.94%,etherified starch increased by 334.11%,356.97%and 124.73%,while the cross-linked starch decreased by 54.54%,67.75%and 31.51%.The freezing-thawing property of three kinds of resistant starch was better than that of starch,and etherified starch had the best freezing-thawing property.The surface of starch granules was smooth and regular and round.The internal and external structures of esterified starch and cross-linked starch were destroyed and lost their original morphology.Etherified starch still maintained the original morphology of starch.Infrared spectrum proved that esterified starch introduced acetyl group,etherified starch introduced carboxymethyl group,crosslinked starch introduced phosphate group.