Bioactive capacity of peanuts with different coat colors

The present work aimed to evaluate three varieties of peanut (Arachis hypogaea L.) regarding the content of anthocyanins and total phenolics, antioxidant activity, phenolic profile and the alkaloids trigonelline and theobromine. The total phenolic content was analyzed by the Fast-Blue and Folin–Ciocalteau methods, while the antioxidant activity was analyzed by the β-carotene/linoleic acid, ABTS⁺ and FRAP methods. The phenolic profile and alkaloids were determined using high performance liquid chromatography (HPLC–DAD-UV–Vis). Peanuts with beige shells stood out with higher antioxidant activity and total phenolic content, while peanuts with purple shells stood out with higher anthocyanin content. Eight phenolic compounds and the alkaloids trigonelline and theobromine have been identified in peanut varieties. However, only four phenolics (gallic, syringic, ferulic and transcinnamic acids), in addition to the two alkaloids, were identified simultaneously in the three varieties studied. Chlorogenic acid was absent in red and purple-seeded varieties, catechin and resveratrol in varieties with red and beige coats, and p-coumaric acid in those with beige coats. For the first time, trigonelline and theobromine were identified in peanuts. Therefore, the bioactive composition and antioxidant activity of peanuts depend on its genotype.