Diagnosis of processes and fermented cashew apple products in Benin

Abstract

In Benin, the cashew apple represents an abundant biomass that remains insufficiently valorized, despite its richness in vitamin C, phenolic compounds, and minerals. Fermented beverages produced from this pseudo-fruit are still based on heterogeneous artisanal processes, predominantly spontaneous, resulting in poorly standardized products. The study, conducted in the Collines, Borgou, and Donga departments, aimed to describe processing practices and to characterize the microbiological and physicochemical properties of the main fermented cashew apple products. The study was based on a field survey of thirty processing units, mostly managed by women, combined with production monitoring and microbiological and physicochemical analyses of fermented musts and final products. The variables investigated included fermentative microbial loads, pH, °Brix, and concentrations of fermentative metabolites. Seventeen derived products were identified, including juice, which was produced in all units, and three main fermented products (alcohol, wine, and vinegar) mainly elaborated from yellow and red phenotypes. Production monitoring showed musts strongly colonized by yeasts and lactic acid bacteria, with counts ranging from 6 to 7 log CFU/mL, associated with marked acidification (pH ≈ 3.6), a decrease in °Brix, and the formation of ethanol and lactic acid. The cashew apple wine obtained exhibited a moderate ethanol content (≈ 58 g·L⁻¹), whereas the vinegar showed an acetic acid concentration of 14.66 g·L⁻¹, lower than values generally reported for controlled fermentations. These results highlight a developing value chain that is nevertheless constrained by high process variability, underscoring the need to implement controlled fermentations based on the selection and valorization of adapted indigenous microbial strains.