脂肪酸链长对高直链玉米淀粉—脂质复合物结构及理化性质的影响

目的：探究淀粉—脂质复合物的形成机理。方法：采用12~18个碳链的脂肪酸与脱支/非脱支高直链玉米淀粉复合，利用差示扫描量热仪、X-射线衍射仪、傅里叶红外光谱仪等分析复合物的热特性、结晶结构及有序结构等，探究脂肪酸链长及脱支/非脱支高直链玉米淀粉对淀粉—脂肪酸复合物结构及性质的影响。结果：脱支处理的淀粉与脂肪酸的复合率随碳链的增长而降低，其中月桂酸复合率最高(15.00%)；未脱支处理的淀粉与脂肪酸的复合率随碳链的增长先升高后下降，其中软脂酸复合率(13.73%)最高。复合物的热特性、结晶结构、分子有序度等与其复合程度有关，淀粉和脂肪酸复合后，糊化峰值温度升高，热稳定性升高，经复合后，淀粉由B型结晶结构转变为V型。结论：脂肪酸链长及淀粉脱支对淀粉—脂质复合物结构及理化性质具有较大影响。

Effects of fatty acid chain length on structure and physicochemical properties of high amylose corn starch-lipid complexes

Objective: This study aimed to investigate the formation mechanism of starch-lipid complex. Methods: Using different fatty acids with carbon chain length of C12~C18 to complex with debranched / non-debranched high amylose corn starch, by measuring the thermal properties, crystalline structure and ordered structure of the complexes with differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectrometer, the effects of fatty acid chain length and debranched/non-debranched high amylose corn starch on the structure and properties of starch-fatty acid complexes were explored. Results: The compound degree of debranched starch and fatty acid decreased with the increase of carbon chain length, and the composite rate of lauric acid (15.00%) was found highest. The degree of composite of non-debranched starch and fatty acids increased first and then decreased with the increase of carbon chain length, and the composite rate of palmitic acid (13.73%) was the highest. The thermal properties, crystal structure and ordered structure of the complexes were related to the compound degree. After forming complexes with fatty acid, the crystal structure of high amylose corn starch changed from B-type to V-type. Conclusion: Fatty acid chain length and starch debranching had great influence on the structure and physicochemical properties of starch-lipid complex.