Antioxidative effect of thyme (Thymus vulgaris) in sunflower oil.

BACKGROUND Lipid oxidation is a main problem during food processing, storage and consumption leading to losses of quality, stability, safety and nutritive value. Antioxidants have been used to prevent oxidation changes and off - flavor development in food products. Aim of the research was to evaluate antioxidative effect of thyme ethanol extract on sunflower oil during its storage in different temperature conditions. Oil samples were stored in darkness at 4°C, 18°C, 38°C. MATERIAL AND METHODS Samples of thyme (thymus vulgaris) were purchased at a local pharmacy in Poznań, Poland and sunflower oil was acquired from a local supermarket. Thyme extract was characterized by total polyphenol content. Antioxidant activity was estimated with use of DPPH and ABTS radicals scavenging methods. Ethanol extract of thyme at 1% level was added to sunflower oil. Peroxide value (PV), anisidine value (AV), totox value (TxV) and fatty acids (FA) content were taken as parameters for evaluation of effectiveness of thyme extract in stabilization of sunflower oil. RESULTS High polyphenol content, DPPH and ABTS radicals scavenging activity of ethanol thyme extract were evaluated. Results from different parameters were in agreement with other researchers, suggesting the antioxidant effect of thyme on antioxidant stability. Results show that thyme extract prolonged stability of sunflower oil and it may be a potent antioxidant for its stabilization. CONCLUSIONS Ethanol thyme extract may be used as a natural antioxidant to prolong stability of oils.