Influence of gamma-irradiation and microwaves on the antioxidant property of some essential oils.

The antioxidant property of anise, caraway, cumin and fennel essential oils extracted from untreated, gamma-irradiated and microwaved fruits against sunflower oil oxidative rancidity was evaluated. The fruits were exposed to gamma-irradiation at 10 KGy and to microwaves at low oven power setting for 1 min. The essential oils were added individually (200 ppm) to sunflower oil and the rate of oil oxidation was followed by determining the peroxide value during storage at room temperature. The irradiated and microwaved essential oils exhibited an antioxidant activity and was superior to that of sunflower oil catalysed by a mixture of BHT + BHA (200 ppm) in most cases. The present data show that gamma-irradiation and microwave treatments did not affect the antioxidant property of the essential oils under study. In addition the essential oils extracted from the gamma-irradiated fruits were more effective as an antioxidant in sunflower oil than those produced from microwaved fruits.