Composition and Antioxidant Activity of Vapours from Clove Bud During Roasting

Abstract

The volatile chemical composition and antioxidant properties of essential oil of clove buds and vapour of roasted clove buds have been revisited together. The major bioactive compounds showed to be eugenol, β-caryophyllene, and eugenol acetate; their different quantitative contribution justifies the unequal aroma and antioxidant properties of clove products. Antioxidant activity of essential oil of clove bud oil and its roasted vapour was measured by 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity,α,α-diphenyl-β-picryl-hydrazyl free radical (DPPH) scavenging activity, total reducing ability determination by Fe3+–Fe2+ transformation method (FRAP) and total phenolic content by TPC. Antioxidant activity of the unroasted clove bud oil is greater than the vapours of the roasted clove bud. Original clove bud (unroasted) contains 89.77 ± 0.03 DPPH, 74.47 ± 0.04 ABTS, 11.1 ± 0.1 FRAP, and 1.15 ± 0.06 TPC, whereas vapours of roasted clove bud contain 60 ± 0.02 DPPH, 72.80 ± 0.03 ABTS, 1.56 ± 0.01 FRAP and 1.44 ± 0.07 TPC. Vapours of the roasted clove bud contain 74.19% eugenol whereas original clove bud (unroasted) contains 94.73% eugenol. Different types of compounds are present in vapours of the roasted clove bud oil.