Influence of carboxymethylation on the gelling capacity, rheological properties, and antioxidant activity of feruloylated arabinoxylans from different sources

ABSTRACT Feruloylated arabinoxylans (FAX) are gelling polysaccharides presenting antioxidant activity (AC) and potential application as delivery systems. The influence of carboxymethylation on the gelling capacity, rheological properties, and AC of FAX from wheat flour (FAX1) and maize distillers grains (FAX2) was analyzed. The degree of substitution of carboxymethyl groups was 0.27 and 1.77 for carboxymethylated FAX1 (CFAX1) and FAX2 (CFAX2), which presented a change in M n from 446 to 362 kDa and from 120 to 180 kDa, and a loss in FA content from 1.05 to traces and from 10.13 to 0.12, respectively, after carboxymethylation. G ′ value at the end of rheological tests for FAX1 (71 Pa) and FAX2 (726 Pa) was higher than the corresponding G ″ value. In contrast, G ″ value for CFAX1 (0.35 Pa) and CFAX2 (0.03 Pa) was higher than the respective G ′ value, indicating that they do no form gels. The AC increased in CFAX1 in relation to FAX1 from 4.49 to 8.30 mmol Trolox equivalent antioxidant capacity (TEAC) kg −1 , respectively, while it decreased in CFAX2 with regard to FAX2 from 11.31 to 9.43 mmol TEAC kg −1 , respectively. Carboxymethylation could be a path to design FAX derivatives offering alternative potential applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48325.