Antioxidant activity of Peanut (Arachis Hypogaea L.) Skin Extract: Application in Soybean and Mustard Oil

Abstract

Total phenolics of peanut skin obtained by different methods were estimated; the effect of different solvents on extractability of total phenolic compounds has also been evaluated. The effect of peanut skin extract, possessing highest phenolics and DPPH radical scavenging activity, was evaluated by schaal oven test in the soybean oil, while oxidative stability of mustard oil was evaluated by Rancimat method. Total phenolics were obtained highest (76.0 ± 2.12 to 101.7 ± 5.54 mg/g GAE dw) in the roasted samples, followed by the dry samples (54.7 ± 1.78 to 89.1 ± 3.78 mg/g GAE dw), and lowest (14.5 ± 0.95 to 21.6 ± 1.02 mg/g GAE dw) in the blanched samples; 80% methanol extraction provided better extractability of phenolic compounds than the aqueous and 80% ethanol extraction method. The peroxide value and induction period of different oils was also evaluated in the present study, which clearly showed that peanut skin extract offered significantly (P < 0.05) better or at least similar protection against oxidation in the oils; than the synthetic antioxidant (BHT). Thus, peanut skin may be a good source of natural antioxidants for stabilization of various vegetable oils, during harsh processing and unavoidable storage conditions.