Optimization of Low-Glycemic Composite Snacks from Wheat, African Yam Bean, Cocoyam, and Date Fruit Flours Using D-Optimal Mixture Design

Abstract

Type 2 diabetes mellitus is prevalent in Nigeria. Its prevention and management depend largely on imported drugs and specialized foods. Often, the items are costly, scarce, and inaccessible. Besides, the acclaimed effectiveness and long-term safety may be false. The challenges underscore the need for affordable, locally produced dietary alternatives. The study developed and optimized composite snack from locally available crops with desirable nutritional quality and a low glycemic index. Wheat, cocoyam (Xanthosoma sagittifolium), African yam bean (Sphenostylis stenocarpa), and date fruit (Phoenix dactylifera) were processed into flours and combined to produce nineteen composite snack samples using a D-optimal mixture design of the response surface methodology. The samples were evaluated for proximate composition, glycemic index, and sensory attributes using standard analytical methods and a 7-point hedonic scale. The results showed that the proximate composition and glycemic index values of the snacks were within recommended ranges. Most of the samples exhibited low glycemic index values, ≤55, indicating suitability for dietary prevention and management of type 2 diabetes. Sensory evaluation revealed moderate to low acceptability and preference, likely due to limited consumer familiarity with composite formulations. Optimization identified a formulation containing 33.3% wheat flour, 22.0% cocoyam flour, 36.7% African yam bean flour, and 10.0% date fruit flour, which yielded 5.01% moisture content, a glycemic index of 7.33, and 7.38% total nitrogen/protein, with an overall desirability of 85%. These findings demonstrate the potential of locally sourced composite snacks as low-glycemic functional foods. Improved nutritional labeling and consumer education may be required to enhance acceptance and preference.