Physical characteristics, chemical composition, and antioxidant properties of defatted grain legumes cultivated in Diamare division (Far North Region, Cameroon)

Pulses have good nutritional, functional, and biological properties and are easily accessible to low-income people. The aim of this work was to study the physical characteristics of the grain as well as the chemical and antioxidant properties of defatted flour from five pulse cultivars (three cultivars of Bambara groundnuts, one of soybean, and one of cowpea) cultivated in the Far North region (Cameroon) and then discuss the therapeutic involvement. Geometric and gravimetric analysis showed that Bambara groundnut cultivars exhibited adequate physical properties. The proximate composition analysis revealed that defatted soybean flour (42.18 %) and Bambara groundnut cultivars (23.58–27.61 %) presented high protein content. High total polyphenolic content was also found in Bambara groundnuts (90.75–103.13 mg GAE/100 g DM), followed by cowpea (96.98 mg GAE/100 g DM). Flavonoid content was noteworthy in soybean flour (61.39 mg EQ/100 g DM). DPPH radical scavenging activity was high in soybean flour (17.61 µg TE/100 g DM), followed by the Bambara groundnuts (14.58–17.41 µg TE/100 g DM). In addition, ferric-reducing antioxidant power (FRAP) was important in Bambara groundnut defatted flour (40.78–43.80 µg TE/100 g DM). The correlation was significant between the physical characteristics, chemical composition, and antioxidant activity of defatted flour. The correlation between total polyphenolic and flavonoid content and antioxidant properties underlined the importance of these compounds in the protection against free radicals and, therefore, in the prevention of metabolic diseases. The high protein and polyphenolic content of these pulse-defatted flours make them a promising raw material for the production of ingredients with biological properties.