Modelling and optimization of processing variables of snack (kokoro) produced from blends of maize and African yam bean seed flour

Abstract

Response surface methodology was used to study the effect of process variables on productquality of fried maize-based snacks (Kokoro). The process variables are African yam bean seed flour (AYBSF) (20-40%) inclusion in maize flour, frying temperature (150-170oC) and frying time (8-12 min). The product’s protein content, sensory quality and color parameters (L*, a* and *) were determined. High-quality Kokoro characterized by high protein content (>10%), highsensory quality (>6.5), and acceptable color parameters [(minimum redness (a*), optimum yellowness (b*) and lightness (L*)] were obtained by using 30% AYBSF, at frying temperature,155oC for 11.5 min. Addition of legume (AYBSF) resulted in significant increases in protein content and sensory evaluation while increasing frying temperature increased the redness and yellowness. Based on the lack of fit test and coefficient of determination, R2, quadratic model was appropriate for protein content, sensory quality, yellowness (b*) and lightness (L*) while linear model was appropriate for redness (a*). Statistical analysis with response regression showed significant (p=0.05) interactions between process variables and quality parameters measured. The optimal process variables of frying temperature 155o C, frying time 11.5 min and AYBSF level (30%) would produce AYB-maize kokoro with enhanced nutritive value, better sensory quality and consistent color parameters.