Comparison of bioactive components, antimicrobial and antimutagenic features of organically and conventionally grown almond hulls

Abstract

In Turkey, almonds are grown via the following three methods: organic (O), conventional (C) and good agricultural practice (GAP). Almond seeds are mostly consumed as nuts; thus, the researchers have focused different analyses on only seeds. However, in Turkey, unripe green almond hulls are also consumed. Therefore, we studied the contents of some bioactive components, pigments, and malondialdehyde (MDA) and the antimicrobial, antioxidant, and antimutagenic activities of O, C, and GAP 'Ferradual' (Frd) and 'Ferragnes' (Frg) almond hull extracts. The highest total ascorbic acid content was found in O Frd (2.1mg/g fresh weight [FW]) and GAP Frg (2.0mg/g FW). The total phenolic content and total flavonoid content in all the genotypes ranged from 19.2 and 43.9mg/g FW and 3.2 and 20.2mg/g FW, respectively. In general, the antioxidant activity of C Frg and C Frd was low. C Frg had the highest MDA content (8.53 mu mol MDA/g FW), whereas O Frg had the lowest MDA content (0.89 mu mol MDA/g FW). The samples had varying ratios of chlorophyll a and b. The O samples had more total carotenoid content than the C samples. The antibacterial activity was only observed in the O and GAP Frd extracts. The antifungal activity could not be detected in any of the extracts of samples. Varying antimutagenic activity inSalmonella typhimuriumTA 98 strain and content of some phenolics were observed depending on the variety, growing conditions, and dose.