Mechanistic Insights Into the Inhibitory Effects of Arabinoxylan and (1,3)(1,4)-β-Glucan on Starch Digestive Enzymes

The intake of dietary fiber can reduce the risk of several major chronic diseases, including colorectal cancer, obesity, type II diabetes, and cardiovascular diseases. Endogenous dietary fibers such as arabinoxylan (AX) and (1,3)(1,4)-β-glucan (BG), which have good palatability, are more suitable for addition to cereal foods. We studied starch digestion in the gelatinized AX/BG–starch complexes. To clarify the synergistic role of AX and BG in the starch digestion process and explore the effect of cell wall polysaccharides on the activity of digestive enzymes, the mechanism of action between cell wall polysaccharides and digestive enzymes was analyzed through fluorescence spectroscopy, UV–visible absorption spectroscopy, and infrared spectroscopy. The results of the interaction between cell wall polysaccharides and digestive enzymes showed that the higher the proportion of AX, the stronger the quenching effect on digestive enzymes and the lower the enzyme activity. During the digestion of the AX/BG–starch complexes, in addition to binding to the active sites of enzymes to reduce enzyme activity, AX and BG played a dominant role as barriers. On one hand, they prevented some water molecules from entering the interior of starch granules to inhibit gelatinization. On the other hand, they effectively reduced the bioaccessibility of digestive enzymes.