Development of Functional Sorghum-Based Foods Fortified with Protein and Probiotics: A Sustainable Solution for Nutritional Security in South African Communities

Department of Biotechnology and Food Technology. Tshwane University of Technology. 175 Arcadia campus, Pretoria, 0184

Abstract

South Africa faces the dual burden of malnutrition and food insecurity, particularly in rural and low-income communities where diets are predominantly carbohydrate-based and lack diversity. It is therefore essential to develop affordable and culturally relevant functional foods. This research explores the potential of fermenting sorghum-protein (cowpea or soya extract) powder mixes with amylolytic probiotic Lactobacillus strains. Two blends were made—sorghum-cowpea (SC) and sorghum-soya (SS)—using a 70:30 ratio. They were pasteurised, inoculated, and fermented under controlled conditions using amylolytic L. helveticus D7 and L. amylolyticus D12. Key aspects measured included fermentation processes like pH and lactic acid, as well as microbial survival, nutritional content, protein digestibility, viscosity and energy. Both food blends showed strong fermentation, with final pH values below 4.0 and lactic acid levels over 0.29%. The counts of lactic acid bacteria exceeded 10⁸ CFU/mL, in both blends over 24 hours, which shows they are safe and have good probiotic potential. The SS blend had a higher protein content (26.4%) and more lysine (6.4 g/100g), while the SC blend provided more iron (6.2 mg/100g) and zinc (3.4 mg/100g). Fermentation improved protein digestibility and lowered thickness in both blends, making them better suited for at-risk groups and children. Changes in energy density and texture confirmed they could be used as nutrient-rich, rehydratable powders or as complementary foods. The findings suggest that both sorghum-cowpea and sorghum-soya fermented blends can be effective, culturally suitable options to improve diet quality and nutritional security in South Africa. The choice between the two formulations depends on the intended use: SS for high-protein clinical applications and SC for affordable, micronutrient-rich nutrition programs at the community level. This work promotes the large-scale development of high-energy, shelf-stable probiotic powders from local crops, thereby supporting food sovereignty and enhancing nutritional outcomes in South African communities.