Bioactive Compounds and Antioxidant Activities of Thyme-Enriched Refined Corn Oil

This study was designed to examine bioactive compounds of the thymeenriched corn oil and to determine the antioxidant activity of its methanolic extract. Volatile compounds composition was investigated by Gas ChromatographyMass Spectrometry (GCMS), whereas phenolic compounds analysis was performed by ReversedPhase HighPerformance Liquid Chromatography (RPHPLC). Antioxidant activities of the flavoured oil methanolic extract were evaluated using DPPH radical scavenging, βcarotenelinoleic acid bleaching, reducing power and total antioxidant assays. Flavoured oil major volatiles were pcymene (26.47%), αthujene (24.06%) and γterpinene (14.30%). Its methanolic extract had higher Total Phenol Contents (TPCs) (53.99 mg 100 g1) than that of the crude oil (23.63 mg 100 g1). Thymol was the main phenolic compound in the flavoured oil (55.84%). Flavoured oil methanolic extract showed higher total antioxidant activity (185.22 mg Gallic Acid Equivalent (GAE) 100 g1) than that of the crude one (100.66 mg GAE 100 g1). In βcarotenelinoleic acid bleaching and DPPH radical scavenging assays, flavoured oil methanolic extract showed higher activities than that of the crude oil based on IC50values. Flavoured and crude oils were characterized by a close CE50values (1.81 and 1.85 mg mL1, respectively). Antioxidant activities of the thymeenriched oil were mainly due to the presence of phenolic compounds such as thymol and hydrocarbons such as γterpinene and p cymene. The thymeenriched oil could be considered as a new and natural source of antioxidant.