Enhancement of the total phenolic and flavonoid contents and antioxidant activity of some fruit peels by solid state fermentation of Trichoderma V6

In the present study, the phenolic and flavenoid contents and antioxidant activity of orange, watermelon and banana peels were evaluated before and after solid state fermentation (SSF) by Trichoderma V6. The results indicated that the extraction by methanol gives high level of phenolic and flavenoid contents compared with water extract. Also, the SSF by Trichoderma V6 increased the phenolic and flavenoid contents of orange, watermelon and banana peels extracted by water and methanol compared with unfermented. The extraction of phenolic compounds by methanol gives high potent antioxidant activity using DPPH assay compared with water extract. The SSF by Trichoderma V6 decreased the IC50 of DPPH of the phenolic compounds indicating the high potent antioxidant activity compared with unfermented phenolic compounds. In conclusion, Orange, watermelon and banana peels are considered good sources of natural antioxidant compounds suitable for food and pharmaceutical applications.