Phytochemical profiles, nutrient compositions, extraction yields and antioxidant activities of seven underground vegetable's peels

Abstract

A large number of studies on fruit's peels revealed the presence of important phytochemicals having diverse biological activities. Here we report the nutrient compositions, extraction yields, phenolic contents and antioxidants activities of the peel samples of seven underground vegetables namely Beta vulgaris, Brassica rapa, Daucus carota, Ipomoea batatas, Raphanus sativus, Solanum tuberosum and Zingiber officinale. Proximate analysis revealed that the peels are good sources of fibers, proteins and ash. The extraction yields of the peels ranged from 8 to 17%, 15 to 32% and 23 to 33% in ethyl acetate, water and methanol, respectively. The flavonoid, phenolic and carotenoid levels were in the ranges of 63.7 to 147.7 mg/100g, 930.0 to 1658.2 mg/100g and 44.0 to 188.3 mg/100g, respectively. The peels also showed good scavenging activities against DPPH radical and hydrogen peroxide.