The effect of oven and microwave roasting on bioactive properties, phenolic components and fatty acid compositions of soybean and peanut seeds

Abstract

The impact of oven and microwave roasting was determined on the phytochemical and bioactive properties of soybean and peanut seeds. When the moisture contents of soybean and peanut seeds were compared to the control, generally the oil content, total phenolic content (except for peanut seeds), and antioxidant capacity of the sseeds increased by roasting processes. The oil contents of soybean and peanut roasted by oven varied between 13.57% (10 min) and 17.68% (30 min) to 48.95% (20 min) and 51.50% (30 min), respectively. The antioxidant activities of soybean and peanut seeds roasted by microwave changed between 3.41% (5 min) and 8.89% (7.5 min) to 30.68% (5 min) and 44.63% (7.5 min), respectively. Gallic, 3,4-dihydroxybenzoic acid, (+)-catechin, 1,2-dihydroxybenzene, quercetin, trans-cinnamic acid, naringenin, kaempferol and isorhamnetin were the main phenolics of soybean and peanut seeds. The oleic acid amounts of the oil extracted from soybean roasted by oven changed between 24.95% (10 min) and 25.48% (20 min) while oleic acid amounts of peanuts roasted by oven vary between 59.96% (10 min) and 60.89% (30 min). The total phenolic amounts of peanuts roasted for different times in the oven and microwave were decreased compared to the control sample, while the total phenolic contents of soybeans roasted in both the oven and microwave showed fluctuations when compared to the control sample.