Abstract: In an effort to comprehensively evaluate changes in the antioxidant activity of fresh-cut Chinese water chestnut during surface etiolation, changes in surface color, flavonoid content and in vitro antioxidant capacity were determined during the storage of fresh-cut Chinese water chestnut. The results indicated that suface flavonoid content increased quickly during etiolation. On the other hand, at the later stage of storage, flavonoid content decreased because of the occurrence of browning. Consequently, the antioxidant capacity increased with storage time, and it reached the maximum level when b* value was the highest, and then remained stable. The statistical analysis showed that b* value had a significant correlation with flavonoid content, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azinobis (3-ehtylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), hydroxyl radical scavenging capacity, ferric reducing antioxidant power (FRAP) and total reducing power (P < 0.01). Similarly, flavonoid content was significantly correlated with DPPH and ABTS+· scavenging capacity, FRAP and total reducing power (P < 0.01). These results indicated that flavonoid content and antioxidant capacity of fresh-cut Chinese water chestnut surface increased due to the occurrence of etiolation.

Key words: fresh-cut Chinese water chestnut, etiolation, flavonoids, antioxidant activity