Fermentation improves the bioactivity of fruit by-products; therefore, this study aimed to increase the bioactive compound content in granadilla ( Passiflora ligularis) seed flour (with 50% and 70% initial moisture) through solid-state fermentation using the fungus Aspergillus niger. The extracts were obtained with distilled water, 40% acetone, 80% acetone, 40% ethanol, or 80% ethanol. The highest total phenolic (4713.3 of gallic acid equivalent/100 g of granadilla seed flour in dry basis) and total flavonoid (1910.4 mg of quercetin/100 g of granadilla seed flour in dry basis) contents were obtained with granadilla flour at 50% initial moisture fermented for 48 h with 80% acetone extractor solvent. The highest antioxidant activity was obtained with 80% acetone from flour fermented for 168 h. The chromatographic analysis showed 10 compounds identified in the 80% acetone extracts of fermented flour; gallic acid and epigallocatechin were the major compounds. Gallic acid, catechin, 6,2′-di-hydroxyflavone, ethyl gallate and coumarin had higher concentrations in extracts of fermented flours when compared with unfermented ones. Only fermented flours showed the presence of protocatechuic acid compound. The solid-state fermentation was efficient to obtain extracts of granadilla seed flour enrichment of antioxidant bioactive compounds with potential of application in food, cosmetic and pharmaceutical industries.
Improving the nutritive value of olive pomace by solid state fermentation of Kluyveromyces marxianus with simultaneous production of gallic acid
