Preparation, characterization, rheological and antioxidant properties of ferulic acid-grafted curdlan conjugates

Abstract In this study, water-soluble curdlan products (Cur and Cur-D) were prepared by an alkali-neutralization treatment process, after which ferulic acid (FA)-grafted Cur conjugates (Cur- g -FA and Cur-D- g -FA) were fabricated in the presence and absence of salt by adopting an approach involving free-radicals generated by the ascorbic acid/hydrogen peroxide redox pair under an inert atmosphere. Results showed that FA was successfully grafted onto the C-6 and C-4 positions of the Cur chains through covalent linkages and that the presence of salt exerted minor influences on the grafting ratios and structural characterizations of the products. Cur- g -FA and Cur-D- g -FA showed decreased crystallinity, thermal stability, and rheological properties, as well as a distinct surface morphology, when compared with those of native Cur. However, Cur- g -FA and Cur-D- g -FA also exhibited remarkably enhanced free-radical scavenging ability and antioxidant capacity in vitro . These results indicate that FA-grafted Cur conjugates have great potential application in the field of functional foods.