脂肪酸碳链长度与不饱和度对脂肪酸-普通玉米淀粉包合物体外消化性质的影响

采用HCl/KOH法制备了脂肪酸-普通玉米淀粉包合物，并采用水解度曲线法测定了包合物的体外消化性质，利用X-射线衍射仪、红外变换光谱分析仪分析了包合物的结晶结构。研究表明，7种脂肪酸均在结晶温度为60 ℃时与玉米淀粉的复合能力最强。除亚麻酸外，玉米淀粉与其余6种脂肪酸的最佳复合比例均为10:1。不同脂肪酸与玉米淀粉形成包合物所需时间不同。脂肪酸与普通玉米淀粉的复合能力随脂肪酸链长及不饱和度的增加逐渐减弱。随着脂肪酸链长及不饱和度的增加，脂肪酸-玉米淀粉包合物的缓慢消化淀粉含量增加，水解率、相对消化率和血糖指数均降低。普通玉米淀粉与脂肪酸复合之后，晶型由A型转变为VI型，结晶度随脂肪酸链长及不饱和度增加而逐渐降低。红外光谱分析结果也表明普通玉米淀粉与脂肪酸形成了络合物。
Fatty acids (FAs) and normal corn starch (NCS) complexes prepared by the HCl/KOH method, were analyzed for in vitro digestibility in terms of the curve for degree of hydrolysis. Additionally, the crystal structure was analyzed using an X-ray diffractometer and a Fourier-transform infrared (FTIR) spectrometer. The results identified seven fatty acids that exhibited the strongest complexation capability with corn starch at the crystallization temperature of 60 ℃. FT-IR spectroscopy confirmed FA-NCS complexation. Except for linolenic acid, the optimal complexation ratio for the six remaining FAs to NCS was 10:1. The time to form inclusion complexes with corn starch varied between the FAs. With increasing chain length and degree of unsaturation, the complexation ability of the FAs with NCS decreased gradually and the content of slowly digestible starch increased, whereas the hydrolysis rate, relative digestion rate, and glycemic index decreased. After forming complexes with FAs, the crystal structure of NCS changed from A to VI, while the degree of crystallinity decreased gradually with increasing FA chain length and degree of unsaturation.