From Waste to Plant‐Based Protein: Impact of Solid‐State Fermentation on Functionality and Protein Extraction of Cassava Leaves

ABSTRACT Background and Objectives Cassava leaves represent a significant waste stream in cassava cultivation, currently underutilized in both food and nonfood applications. This study investigates the use of solid‐state fermentation with Aspergillus oryzae , Lactobacillus plantarum , and Bacillus subtilis to modify the composition and functional properties of cassava leaf flour (CLF), as well as to serve as a pretreatment for wet fractionation aimed at producing higher protein ingredients. Finds Results showed that fermentation increased the protein content of CLF while reducing anti‐nutritional compounds. Fermentation had no significant effect on water‐holding capacity or protein digestibility, but it increased oil‐holding capacity and decreased solubility. Alkaline extraction followed by isoelectric precipitation was applied to extract proteins from the fermented CLF; however, fermentation did not improve protein availability, as evidenced by the lower protein purity of the concentrates when compared to non‐fermented samples. Nevertheless, the functional properties of the protein concentrates obtained from the fermented cassava leaves were improved, demonstrating a positive effect of fermentation on the extracted protein's techno‐functional potential. Conclusions Overall, fermentation increased the protein content of CLF, reduced anti‐nutritional compounds, and enhanced the functional properties of the extracted protein. Significance and Novelty These findings suggest that fermentation of cassava leaf flour represents a viable biotechnological strategy for sustainable food industry applications, contributing to the development of more sustainable food supply chains.