Catechin-grafted arabinoxylan conjugate: Preparation, structural characterization and property investigation

In this study, a highmolecular weight arabinoxylan (AX, Mw: 694 kDa) from wheat bran was alkaline extracted and covalently linked with Catechin (CA) by free radical catalytic reaction. Comparing to AX, arabinoxylancatechin (AX-CA) conjugates demonstrated an extra UV-vis absorption peak at 274 nm, a new FT-IR absorption band at 1516 cm(-1) and new proton signals at 6.5-7.5 ppm, which all confirmed the covalently linked structure. Grafting CA onto AX not only decreased themolecularweight, thermal stability and apparent viscosity of AX, but also enhanced its inhibition effects on starch digestibility in vitro. The in vitro fermentation test with pig feces showed that the degradation & utilization rate of AX, the total short-chain fatty acid (SCFA) and acetic acid levels produced all were significantly delayed after grafting. This study provided a novel approach to synthesize AX-CA conjugates that could be a novel dietary fiber of enhanced functional/bioactive properties using in the fields of functional foods and medicine. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, a novel approach to synthesize AX-CA conjugates was proposed by covalently linking a high molecular weight arabinoxylan (AX) with Catechin (CA). The AX-CA conjugates showed altered characteristics compared to AX, with decreased molecular weight, thermal stability, and enhanced inhibition effects on starch digestibility, as well as delayed degradation and utilization rates in in vitro fermentation tests using pig feces. This research provides insights into the potential of AX-CA conjugates as a novel dietary fiber with enhanced functional and bioactive properties for applications in functional foods and medicine.