Valorization of peanut meal through solid-state fermentation: Enhancing protein functionality and reducing aflatoxins, allergenic and anti-nutritional factors

Abstract

The increasing demand for sustainable and nutritious food ingredients has intensified interest in the valorization of agro-industrial side streams. This study investigated the impact of solid-state fermentation (SSF) on the nutritional quality, safety, and techno-functional properties of peanut meal, with emphasis on relative increases in crude protein content on a dry matter basis, reduction of ELISA-detectable allergenic proteins, and improvements in aflatoxin safety. Selected bacterial and fungal strains (Bacillus subtilis, Rhizopus oryzae, and Aspergillus oryzae) were applied under strain-specific optimized SSF conditions to evaluate the overall effect of the bioprocess on peanut meal as a food ingredient. Thermal processing followed by solid-state fermentation resulted in a relative increase in crude protein content on a dry matter basis and promoted substantial reductions in total aflatoxins, a decrease in detectable allergenic proteins, and antinutritional factors when compared to the untreated peanut meal. In addition, SSF significantly improved key functional and physical properties, including swelling capacity, foaming ability, and oil-holding capacity. Taken together, these results demonstrate that solid- state fermentation is a simple and scalable bioprocess for converting low-value peanut by-products into nutritionally enhanced and functionally improved protein ingredients with improved safety-related attributes, suitable for food applications.