Composition of phenolic and antioxidant activity of water chestnut peel during digestion in vitro as affected by blanching time

ABSTRACTWater chestnut peels have good antioxidant activity. The effects of simulated gastric fluid (SGF) and intestinal fluid (SIF) fluid digestion in vitro on the active substance and antioxidant activity of water chestnut peels that were pre-treated using different boiling times (P10 and P30) were investigated. The results showed that the SGF obviously increased both the total phenolic content and total flavonoid content of water chestnut peels. The SGF digestion significantly enhanced both the FRAP and ABTS antioxidant capacity of water chestnut peels only blanched with P10. However, the SIF digestion significantly increased the FRAP and ABTS antioxidant capacity of all water chestnut peels regardless of whether these were pre-treated or not. The HPLC results showed that the simulated digestion in vitro enhanced the flavonoids content of the peels. Water chestnut peels could be used as an inexpensive source of natural functional food ingredients.