Solid state fermentation of fig (Ficus carica L.) by-products using fungi to obtain phenolic compounds with antioxidant activity and qualitative evaluation of phenolics obtained

An optimized method of solid-state fermentation (SSF) is reported for the valorization of fig (Ficus carica L.) by-products. Four fungal strains were screened for their capacity to enhance the release of total phenolic compounds (TPCs). Temperature, pH, moisture, and mineral composition were evaluated and optimized using a Box Hunter Hunter design and then central composite design was performed. The optimized SSF conditions were as follows: A. niger HT4 for 36 hat 40 degrees C; moisture, 60%; pH: 5.0; mineral composition (g/L): NaNO3: 0.57; KH2PO4: 3.04; MgSO4 center dot 7H(2)O: 1.52; and KCl: 5.37. Under the optimal SSF conditions, the experimental values (10.19 +/- 0.04 mg of GAE/g of dm) matched with those predicted (10.37 mg of GAE/g of dm) within a 95% confidence level. A total of eight phenolic compounds were identified by High Performance Liquid Chromatography -Mass Spectrophotometry (HPCL-MS). The optimized SSF bioprocess increased the TPC release and antioxidant activity values up to 5.48 and 98.54 times, respectively, showing its feasibility as a reliable alternative for the use of fig by-products.