Starch-guest inclusion complexes: Formation, structure, and enzymatic digestion

Starch/amylose-guest inclusion complexes, a class of supramolecular host-guest assemblies, are of critical importance in the processing, preservation, digestion, nutrients/energy uptake, and health outcomes of starch-containing foods. Particularly, the formation of inclusion complex has been suggested to lower the rate and extent of enzymatic digestion of starch and starch-containing foods. Compared with rapidly digestible starch, starch inclusion complex may fall into the category of slowly digestible starch, providing sustained glucose release and maintaining glucose homeostasis. Therefore, the ability of starch-guest inclusion complex to alter the digestive behavior of energy-dense starchy foods has been of interest to many researchers and has the potential to be developed and formulated into functional foods. In this article, we provide a comprehensive and critical review on the current knowledge of the in vitro and in vivo enzymatic digestion of starch-guest inclusion complexes, by emphasizing the structure-digestibility relationship. We examine the preparation methods employed, crystalline structures obtained, and physicochemical properties characterized in previous reports, which all have implications on the digestive behavior reported on the starch-guest inclusion complexes. In addition, we give suggestions on future research to elucidate the digestive properties of starch-guest inclusion complexes and to develop functional structures based on these complexes for use in foods and nutrition.