Evaluation of the nutritional and bioactive composition of peanut by-products: peanut skins obtained after roasting

Abstract Peanut skins (PS) are the main by-product of peanut processing in agro-industries. They contain numerous bioactive compounds that provide health benefits. In Burkina Faso, PS are underutilized and ultimately considered waste due to the lack of awareness of their medicinal properties. This study aimed to evaluate the nutritional and bioactive composition of PS obtained after roasting two cultivars widely grown and consumed in Burkina Faso. The findings showed that both PS samples contained substantial amounts of dietary fiber (38.6-43.0 g/100 g), total carbohydrates (57.16-69.86 g/100 g), proteins (12.26-14.52 g/100 g), and lipids (13.58-23.44 g/100 g). Mineral analysis revealed high levels of magnesium (110.73 -121.73 mg/kg), calcium (25.25-74.5 mg/kg), zinc (15.01-26.02 mg/Kg), and iron (7.50 -10.01 mg/kg). Amino acid composition analysis indicated that glycine, glutamic acid, aspartic acid, and serine were predominant. Furthermore, the cultivars exhibited variable concentrations of bioactive compounds, including total polyphenols (138.75-145.19 mg GAE/g), flavonoids (46.25-48.39 mg QE/g), phytate (748.92 -10.68 mg/g), condensed tannins (1.06-4.29 mg/g), salicylic acid (11.52-21.35 μg/g), lycopene (283.59-362.53 μg/g), β-carotene (293.87-21.95 μg/g) and ascorbic acid (0.52-3.25 μg/g), which collectively indicate notable antioxidant potential. Overall, these findings suggest that PS can be used to enrich various food products, enhancing their nutritional value.