Efficacy of phenolic compounds from bay leaf (Laurus nobilis) as natural antioxidants in the enhancement of edible oil thermo-resistance.

Edible oils are lipids rich in polyunsaturated fatty acids, making them susceptible to oxidation and requiring supplementation with synthetic or, more interestingly, natural antioxidants. The present investigation aimed to evaluate the use of phenolic compounds extracted from bay leaves for enhancing the thermo-stability of soybean oil. Soybean oils prepared with different concentrations of a phenolic extract (20, 40 and 60 mg/l) and the control oil were evaluated during heat treatment (170°C, every 24 h for 3 days) by monitoring UV absorption coefficients, acidity, peroxide value, iodine value as well as total phenolic content and antioxidant activity. The results showed that the phenolic compounds of bay leaf reduced the incidence of thermo-oxidation of soybean oil, as manifested by lower UV absorption coefficients, acidity, and peroxide value, and protected the double bonds better. This protection was more efficient when the phenolic concentration increased, and this was related to their antioxidant activity. The phenolic compounds of bay leaves, especially at 60 mg/l, demonstrated the best efficiency in enhancing the protection against thermo-oxidation of soybean oil during heat treatment, which opens some perspectives for their use in the oil industry. [ABSTRACT FROM AUTHOR]