CHARACTERISATION OF PRETREATED BROWN COWPEA(VIGNA UNGUICULATA) SEED COAT

ABSTRACT Cowpea seed coat, a byproduct of dehulling, offers significant nutritional value and potential therapeutic benefits. However, evidence abound on the concentration of anti-nutrients on the seed coat. This study investigated the impact of sodium bicarbonate soaking and fermentation pretreatments on the nutrient, phytochemical, and antioxidant properties of cowpea seed coats with the aim of promoting their utilization in functional food formulations. Brown cowpea seeds called ‘drum’ beans were procured locally. The beans were soaked in water (28±2 °C, 30 min) and manually dehuled to obtain the seed coat for the study. Dried seed coats (55 °C, 5 h) were subjected to two pre-treatments; soaking in sodium bicarbonate solution (2 and 3% concentration, 1 h) and wild fermentation (24 and 48 h). The pretreated seed coats were dried (55℃, 4 h) and untreated seed coat served as control. The pretreated seed coat were analysed for proximate components, phytochemicals (total phenols and total carotenoids); antioxidant activities (DPPH, FRAP); anti-nutrients (phytate, saponins, oxalate and trypsin inhibitor) and functional properties. The data obtained were subjected to ANOVA and means were separated using Duncan multiple range tests. Results showed that both pretreatments effectively reduced antinutrients while preserving essential nutrients. Furthermore, the pretreated seed coats exhibited enhanced antioxidant activity and phytochemical content. Specifically, moisture content ranged from 9.10% to 10.50%, fat content from 4.17% to 4.70%, ash content from 0.73% to 0.91%, crude fiber from 15.81% to 19.87%, crude protein from 62.96% to 67.27%, and carbohydrate content from 62.96% to 67.27%. Antinutrients, including phytate, saponins, oxalate, and trypsin inhibitor, were significantly reduced. Total phenolic flavonoids ranged from 0.133 mg/100g to 0.283 mg/100g, total carotenoids from 0.212 mg/100g to 0.639 mg/100g. Antioxidant activities, as measured by FRAP, ABTS, and DPPH, were significantly improved. These findings suggest that cowpea seed coats, when properly processed, could serve as a valuable ingredient in functional food formulations, offering a sustainable and nutritious option for consumers.