Abstract
The objective of this study was to compare the antioxidant capacities of eugenyl acetate, eugenyl butyrate, eugenol/eugenyl acetate combinations, and eugenol/eugenyl butyrate combinations in canola oil at frying temperature (180°C). Eugenol and a synthetic antioxidant (BHT) were considered as reference in terms of antioxidant capacity. Eugenyl acetate and eugenyl butyrate were produced by autocatalytic reactions through microwave heating. Eugenyl acetate was more effective than eugenol and eugenyl butyrate in reducing the anisidine value and total polar compounds in canola oil during heating at frying temperature. In addition, the combinations of eugenol/eugenyl acetate (50/50%, wt/wt) and eugenol/eugenyl butyrate (25/75, 50/50, and 75/25%, wt/wt) were more effective than each of the antioxidants alone in reducing the oxidation of canola oil. More time was required to achieve the upper legal limit of total polar compounds in canola oil when different antioxidant compounds were added to the oil. Practical applications: Eugenol, the major compound in several important essential oils is known to have strong antioxidant activity. However, the exposure of eugenol to high temperatures makes it chemically instable, thereby limiting its applications in food industry. Modifying the structure of phenolic compounds via esterification can be used as an effective method to maintain it effectiveness at high temperature. Hence, this study was designed to evaluate the thermal stability of eugenol, eugenyl acetate, eugenyl butyrate, and combinations of eugenol/eugenyl acetate and eugenol/eugenyl butyrate during heating at frying temperature.