Changes in quality, bioactive compounds, fatty acids, tocopherols, and phenolic composition in oven- and microwave-roasted poppy seeds and oil

Abstract

The oil quality, fatty acid composition, tocopherol contents, and phenolic compounds of oven- and microwave-roasted seeds from three different poppy varieties (blue, yellow, and white) were investigated. The quantity, acidity, unsaponifiable matter, peroxide, and saponification values of oil were generally higher in roasted seeds compared to those in raw poppy seeds (control). Total phenolics, flavonoids, anthocyanin contents, and antioxidant activity of roasted seeds were less than those of the control. Roasting decreased fatty acid contents including linoleic acid in blue, yellow, and white seeds and its contents remained 57.91, 61.91, and 64.83% in control oil (oil from raw seeds) but decreased to 57.23, 60.78, and 64.11% in oven-roasted and 56.97, 60.08, and 60.84% in microwave-roasted seed oil, respectively. The tocopherol (α, β, γ, and δ) contents also decreased after roasting and β and γ-types predominated. The major phenolic compounds were vanillic, p-hydroxybenzoic, ferulic, p-coumaric,cinnamic, and protocatechuic acids. The vanillic acid content ranged from 64.38–71.17 mg/100 g in raw seed, 41.86–49.76 mg/100 g in oven-roasted, and 43.66–56.71 mg/100 g in microwave-roasted seed. The current study revealed that poppy seeds and their oil have excellent nutritional qualities that are significantly reduced after roasting.