压热辅助酶解法制备马蹄抗性淀粉的工艺优化及理化特性研究

Process Optimization and Physicochemical Characteristics Research of Water Chestnut Resistant Starch Prepared by Pressure and Heat Assisted Enzymatic Hydrolysis

为探究压热辅助酶解法制备马蹄抗性淀粉的最优工艺及特性,以马蹄淀粉为原料,设计淀粉乳浓度、酶添加量、酶处理时间3个单因素,并以制备后样品中的抗性淀粉得率为响应值对工艺条件进行优化,同时对样品进行扫描电镜(Scanning electron microscope,SEM)观察并测定直链淀粉和支链淀粉含量等理化特性。结果表明,淀粉乳浓度25.56%、酶添加量15.87 ASPU/g(干基)、酶处理时间35.75 h为最优的制备工艺,在此工艺下得到的抗性淀粉得率最高为16.32%,与预测值16.1093%相近,证明响应面模型与实际情况拟合良好。理化特性研究发现:抗性淀粉中的直链淀粉含量为31.78%,显著高于原淀粉,是原淀粉的242.9%;碘吸收特性曲线发现,原淀粉的最大吸收峰在600~650 nm之间,抗性淀粉的最大吸收峰在550~600 nm之间,抗性淀粉的λmax相对原淀粉出现了左移,表明抗性淀粉中直链淀粉与支链淀粉比例发生了改变;红外光谱分析发现,抗性淀粉的R1047/1022值和R1022/995值均高于原淀粉,表明抗性淀粉具有更高的结晶度。研究结果可为压热辅助酶解制备马蹄抗性淀粉的应用提供理论依据。

In order to explore the optimal process and characteristics of water chestnut resistant starch prepared by pressure and heat assisted enzymatic hydrolysis,this experiment used water chestnut starch as raw material,designed three single factors:starch milk concentration,enzyme addition and enzyme treatment time,and optimized the process conditions with the yield of resistant starch in the prepared sample as the response value.At the same time,the samples were observed by scanning electron microscope(SEM)and the contents of amylose and amylopectin were determined.The results of process optimization showed that the optimum preparation process was starch milk concentration of 25.56%,enzyme addition of 15.87 ASPU/g(dry basis),and enzyme treatment time of 35.75 h.The highest content of resistant starch obtained under this process was 16.32%,close to the predicted value of 16.1093%,which proved that the response surface model fitted well with the actual situation.The study of physicochemical characteristics showed that the content of amylose in resistant starch was 31.78%,which was significantly higher than that of original starch,and was 242.9% of original starch.The iodine absorption characteristic curve showed that the maximum absorption peak of raw starch was 600-650 nm,the maximum absorption peak of resistant starch was 550-600 nm,λmax shifted to the left relative to the original starch,indicating that the proportion of amylose and amylopectin in resistant starch had changed.The results of infrared spectroscopy showed that the R1047/1022 and R1022/995 values of resistant starch were higher than those of original starch,indicating that resistant starch had higher crystallinity.The results of this study can provide a theoretical basis for the preparation of water chestnut resistant starch by pressure and heat assisted enzymatic hydrolysis.