Protein enrichment of cassava flour by Saccharomyces cerevisiae fermentation and development of a muffin

Protein enrichment of cassava flour by fermentation using Saccharomyces cerevisiae was developed, and a product was designed and investigated. The study comprised optimization of incubation time for 48 to 96 h at 25 to 35^oC of the fermentation design of cassava flour-based substrate. Experimental design for the fermentation optimization for the maximum protein content was performed by using Response surface methodology-Central composite design (RSM-CCD) experimental design with 13 experiments. The optimized conditions for the ideal fermentation process were obtained at 35 °C for 96 h incubation time, leading to optimal protein content (5.43%) in the final fermented cassava flour. The coefficient of variation (CV) was 10.17%, indicating the model’s excellent experiment reliability. The optimized fermented flour was validated by developing a muffin as a product. The partial substitution of wheat flour (WF) with solid-state fermented cassava flour (SCF) at around 23.07% enhanced the physical properties of muffins (viz., texture, color, flavor). The effect of partial replacement of WF by SCF (up to 23.07%) resulted in decreased batter density and increased specific volume after baking. The micrograph images of the muffin validated the relationship between the batter density, bubble size, and distribution. Muffins made with WF and SCF (at 77:23 w/w) had significantly higher softness, appearance, and overall acceptance scores than those made with only WF (P ≤ 0.05). SCF can be used as an ingredient for food product development with its added nutrient enrichment and texture-modifying properties.