Effects of freeze–thaw pretreatment on the structural properties and digestibility of lotus seed starch–glycerin monostearin complexes

To investigate the effects of freeze–thaw cycle pretreatment (in one cycle, frozen samples were reheated to 50 °C and then frozen at −20 °C) on the structural properties and digestibility of lotus seed starch–glycerin monostearin complexes, their complex index, crystal structure, molecular structure, micro-morphology, and digestibility were analyzed. The results showed that an appropriate number of freeze–thaw cycles facilitated the helical assembly of lotus seed starch and glycerin monostearin. Specifically, six cycles of freeze–thaw pretreatment were favorable for forming V6I-type complexes with high microcrystalline proportion. This contributed to the high stability of crystalline region and order arrangement of molecular structure. Moreover, V6I-complexes were in the form of lamellar debris in micro-morphology, and their total digestion and digestion rates were lower than those of other samples. These results were of significance for developing slowly digesting lotus seed starch-based food.