Crosslinked arabinoxylan reduced the starch digestibility through inhibiting the enzyme activity of α-amyloglucosidase but not α-amylase

Abstract

Arabinoxylan hydrogels, specifically crosslinked arabinoxylan (CLAX), have been demonstrated to attenuate the digestibility of starch. However, the underlying inhibitory mechanisms remained obscure. In the present study, three CLAXs, including the high crosslinked arabinoxylan (H-CLAX), medium crosslinked arabinoxylan (M-CALX), and low crosslinked arabinoxylan (L-CLAX) were fabricated to investigate their inhibitory mechanism on starch digestion. Notably, all CLAXs were observed to enhance α-amylase activity while reducing α-amyloglucosidase (AMG) activity. Among them, H-CLAX exhibited the most pronounced inhibitory effect (67.3°%) on AMG, followed by M-CLAX and L-CLAX. Fluorescence quenching assays indicated that the inhibitory interaction of CLAX with AMG is attributable to static quenching. Inhibition kinetic analyses further classified CLAX as an anti-competitive inhibitor, interacting with the non-active sites of the AMG-starch complex. Confocal laser scanning microscopy substantiated these interactions. The insights gained from this study shed light on the mechanisms by which CLAX influences postprandial glycemia, providing a scientific basis for its application in controlling blood sugar levels.