Effect of lauric acid on the V-amylose complex distribution and properties of swelled normal cornstarch granules

•Starch–lipid complex was prepared using lauric acid (LA) and swollen cornstarch.•Higher incubation temperature could improve the degree of complexation.•The modes of adding LA would influence the formation and distribution of complex.•The starch–LA complex showed the ability of slowing the hydrolysis of starch.

Starch–fatty acid complexes were prepared using swelled normal cornstarch (NC) and lauric acid (LA). Two different modes of adding LA to the starch slurry were employed; i.e. either adding the LA to the heated starch suspension (method I) or adding the LA to the starch suspension and then heating (method II). Effects of the modes of adding LA on the V-amylose complex distribution and digestibility were studied. Lipid content determination indicated that method I is favorable to the formation of V-amylose complex. Light and confocal laser scanning microscopic examination indicated that NC–LA complex prepared by method I seemed to be more swollen, and the V-amylose complex distributed throughout the granules, while NC–LA complex prepared by method II was mainly distributed on the surface of starch granules. The results of X-ray diffraction and thermal property demonstrated that method I was more beneficial to the formation of more crystalline structure than that of method II. The in vitro digestibility investigation showed that the addition of LA through method I had the ability of slowing the hydrolysis of starch.