Plant-based foods have health benefits and minimal side effects than synthetic anti-diabetic agents. Therefore, this study evaluated nutritional and anti-hyperglycaemic efficacies of raw African star apple (RASA) and fermented African star apple seeds (FASA). Methodology: The RASA and FASA seeds were processed into flour, and nutritional qualities, antioxidative and antidiabetic activities in wistar rats were evaluated at different concentrations (i.e., 20, 30, 40% ASA) respectively. Results: Crude protein (g/100g) and energy values (kcal/100g) of RASA and FASA ranged as follows: 11.8 - 23.9 and 372.1 - 417.5 respectively. The Na/K (1.11 – 1.72) and Ca/P (12.71 – 18.71) molar ratios of RASA and FASA samples were greater than recommended values of <1.0 and >1.0 respectively. Total essential amino acids of RASA and FASA were 33.14 and 48.48 g/100g of protein respectively, while predicted protein efficiency ratio, essential amino acid index and biological value were 2.25 – 3.29, 58.43 – 83.68% and 51.99 – 79.51% respectively. Tryptophan and methionine were the first and second limiting amino acids in RASA and FASA respectively. FASA had higher free radical scavenging activities in DPPH, FRAP and metal chelation inhibitory activities than in RASA. Blood glucose lowering effects of RASA and FASA in diabetic-induced rats increased as the concentration of ASA increased (i.e., 89% RASA40%, 78% FASA40%). Conclusion: The African star apple seeds could be valuable and excellent source for low-priced functional foods, and the seeds are characterized by essential nutrients, crude fiber, ability to scavenge free radicals and blood glucose lowering potentials.
Keywords: African star apple seeds, Nutritional quality, Antioxidant, Anti-diabetic potentials