EFFECT OF SOLID-STATE FERMENTATION ON THE COMPONENT PROFILE OF DIFFERENT COWPEA FLOURS

Cowpeas are a legume rich in proteins, vitamins, minerals and bioactive compounds  with antioxidant properties. However, it contains anti-nutritional factors that hinder nutrient absorption. Solid-state fermentation (SSF) is an effective strategy for reducing these compounds and increasing the bioavailability of nutrients. This study evaluated the effect of FES on cowpeas using the fungus Pleurotus ostreatus to produce a flour with an improved nutritional profile. FES was carried out using 70g of cowpeas in a ratio of substrate:distilled water (1:0,74) and inoculation of 264 mg/100 mL of the fungal solution, fermented for 14 days at 28 °C, followed by drying at 60 °C for 48 hours. Three bean flours were evaluated: control (CF), autoclaved (AF) and fermented (FF). The results showed that FES reduced the pH of the flours from 6,47^a (CF) – 6,41^a (AF) to 5,51^c (FF), probably due to the acidification resulting from fermentation. Water activity varied from 0,552^a, 0,3037^c and 0,4247^b for FC, AF and FF, respectively. In the colour analysis, the L*, a* and b parameters showed significant differences. For the L* parameter, values of 85,25^a, 85,25^b and 66,75^c were obtained for CF, AA and FF, respectively. Similarly, for the a* and b* parameters, the values were 7,7067^a, 0,8467^b,28,100^c, and 16,4567^a, 17,8567^b, 26,8933^c. These changes show significant darkening, possibly related to mycelial changes due to exposure to heat during the autoclaving of the flours. The protein content increased significantly from 18,49^b (CF) to 24,91^a (FF), due to the growth of the fungal biomass. Furthermore, the phenolic compounds increased from 0,6301^b mg gallic acid/dry matter in CF to 3,0434^a mg gallic acid/dry matter in FF, indicating that fermentation favoured an increase in the phenolic compound content. It can therefore be concluded that fermented cowpea flours have the potential to improve the nutritional value of food products.