Different starch varieties influence the complexing state and digestibility of the resulting starch-lipid complexes

Abstract

In this study, we investigated the complexing state and digestibility of complexes formed between myristic acid (MA) and several varieties of starch (maize starch, MS; waxy maize starch, WS; high amylose maize starch, HMS; rice starch, RiS; cassava starch, CS; potato starch, PS). The resistant starch (RS) content, complexing index, and degree of the structural order of HMS-MA and MS-MA complexes were significantly higher (p < 0.05) than those of the other complexes. Notably, the RS increments of MS-MA complexes were the highest (14.10%). CS-MA, MS-MA and RiS-MA complexes showed better thermal stability of starch than the other complexes. The MA molecules were primarily physically embedded outside the helical structure of starch in WS-MA and PS-MA complexes. Additionally, CS-MA complexes possessed the highest relative number of physically embedded MA molecules. Moreover, the distribution of physically embedded MA molecules in WS-MA, CS-MA, and PS-MA complexes was more homogeneous than that in the other complexes. The weight-average molecular weight of amylose, average chain length of amylopectin side chains, and the proportion of chains with a degree of polymerization of 6–12 and 25–36 greatly affected their interactions with MA molecules. These results indicated that starch types substantially influenced the digestibility of the complexes, which was closely related to their complexing state and structural order.