Effects of the interaction between konjac glucomannan and starch on the physicochemical properties, recrystallization characteristics, and digestibility of starch: A review

The physicochemical, recrystallization, and digestibility properties of starch play a crucial role in both the food industry and human health. Konjac glucomannan (KGM), a water-soluble dietary fiber, is famous for its excellent thickening and gelling properties, which can interact with starch during food processing and affect its properties. However, the interaction between KGM and starch and the effects and mechanisms of these interactions on the subsequent physicochemical and recrystallization properties and digestibility of starch have not been fully discussed. This paper reviewed and analyzed the effects of KGM on starch's digestibility and physicochemical and recrystallization properties in recent years. It also discussed in detail the specific mechanisms by which KGM affects starch pasting, gelatinization, retrogradation, swelling, rheology, textural properties, recrystallized microstructure, recrystallized crystal structure, and digestibility, as well as the compounding methods of KGM and starch. KGM restricts starch's water ingress and heat transfer by competing with starch for available water, affecting starch gelatinization, retrogradation, swelling, and digestibility. The adhesion system formed by KGM and the dense and orderly gel network formed by the interactions between KGM and starch through non-covalent forces can be used as a physical barrier between starch and digestive enzymes to restrict enzymes molecular movement, reducing starch digestibility. The effects of KGM on starch's various properties are determined by many factors, including but not limited to KGM's molecular structure, concentration, and complexation methods. This review provides important insights for understanding of the interactions between starch and KGM and contributes to advancing KGM applications in starch industry.