Abstract: The effect of cabbage maturity on the monosaccharide composition and antioxidant activity of cabbage dietary fiber was studied. The data obtained suggested that, with cabbage maturation, the content of soluble dietary fiber (SDF) kept decreasing, whereas insoluble dietary fiber (IDF) and total dietary fiber (TDF) tended to firstly increase and then drop. The constituent monosaccharides of cabbage dietary fiber at different maturity stages were identical, namely galacturonic acid, glucuronic acid, glucose, galactose, rhamnose and arabinose, despite a significant difference in their percentages. In the case of cabbage SDF, with the increase in maturity, the percentage of glucuronic acid decreased, glucose and galactose increased significantly, and galacturonic acid, rhamnose and arabinose showed a parabola, reaching its peak at maturity B. As for cabbage IDF, with increasing maturity, the percentages of glucuronic acid and galacturonic acid increased significantly, glucose and galactose had no change at first and then decreased significantly starting from maturity D, arabinose showed a parabola reaching the highest level at maturity D, and rhamnose had no significant difference. The antioxidant activity of cabbage dietary fiber was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging capacity, and ferric reducing antioxidant power (FRAP). Our results showed that the DPPH radical scavenging capacity and FRAP of cabbage SDF and IDF significantly increased with cabbage maturation, and the ABTS radical scavenging capacity at maturity C was at the highest level.

Key words: cabbage maturity, dietary fiber, composition analysis, antioxidant activity