Added dietary fiber reduces the antioxidant capacity of phenolic compounds extracted from tropical fruit

Abstract

The effect of dietary fiber (DF) from tropical fruits on the antioxidant capacity of phenolic compounds (PC) present in the same fruits was investigated. DF obtained from tropical fruits pulp (FDF) was incubated with methanolic extracts (ME) containing PC, at pH 2.5 and room temperature for 2 h. The total soluble phenols (TSP) content and antioxidant capacity (DPPH assay) were analyzed in the resulting supernatants. Results show that the addition of FDF significantly (p<0.05) decreased the antioxidant capacity of ME from 5-20%. Among the FDF, the mango fiber affected in higher extent the antioxidant capacity. Wheat dietary fiber (WDF) was used as control. The addition of WDF decreased significantly (p<0.05) the antioxidant capacity ranging from 23-45%. The bioactive compounds bioaccesibility was also reduced with both types of fiber, being the WDF the most effective to trapping the PC. This suggests that apparently some type of physic-chemical interaction between DF and PC are occurring consequently affecting the bioaccesibility and action of antioxidants.

Keywords

• phenolic compounds
• dietary fiber
• tropical fruits
• bioaccesibility