Nutritional, Antioxidant, and Functional Properties of Cameroonian Cowpea and Bambara Groundnut and Their Culinary Forms.

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Background Voandzou and cowpea are two legumes commonly used in African dishes as alternative sources of proteins. The present study aimed to evaluate the effects of steaming and frying on the nutritional and functional properties of Cameroonian cowpea (Vigna unguiculata) and Bambara groundnut (Vigna subterranea). Methodology The nutritional values, as well as the antioxidant, alpha-amylase, and alpha-glucosidase inhibitory activities of "koki" and "beignet koki," which are the traditional steamed dish and fritters made from cowpea and Bambara groundnut, respectively, were assessed. Results All the legumes displayed high levels of lipids, proteins, and carbohydrates. It was observed that both steaming and frying increased the lipid content and the energy values of cowpea and Bambara groundnut while simultaneously reducing the protein and carbohydrate contents. Both raw and processed legumes contained varying amounts of the minerals examined, with the treatments having inconsistent effects on them. The total phenolic content (TPC) and total flavonoid content (TFC) were significant in both legumes, with cowpea exhibiting the highest levels (TPC of 676.46 ± 16.87 µg gallic acid equivalents (GAE) per gram of extract and TFC of 219.27 ± 4.62 mg quercetin equivalents (QE) per gram of raw brown and black-eyed cowpeas, respectively). The antioxidant capacities, measured using different methods, were negatively impacted by both steaming and frying due to the destruction of their bioactive compounds. The alpha-amylase and alpha-glucosidase inhibitory capacities of both legumes experienced similar reductions after culinary treatments. Conclusions Cowpea and Bambara groundnuts are valuable sources of proteins, energy, and antinutrients. They are sufficiently rich in phenolic compounds with antioxidant and inhibitory effects on alpha-amylase and alpha-glucosidase. Consequently, these legumes can be used as functional foods. Stifled cooking and frying reduce mineral content (except for sodium), bioactive compound levels, and antioxidant, alpha-amylase, and alpha-glucosidase inhibitory capacities of the studied legumes.