Effect of Gamma Radiation on Oil Quality of Dried Mint Leaves

The green mint crop is considered a medicinal and aromatic plant grown in most of Egypt's governors and it has multiple uses, whether it is used fresh or dried or mint oil is extracted from it and mint is also known as its medicinal importance as research has proven that it has many health benefits. This research was conducted to study the effect of gamma irradiation on the oil quality assessment of dried mint leaves. Dry mint leaves were treated by using doses of gamma radiation, 0.0, 5, 10, 15 and 20 kGy. The color properties as Chlorophyll a, Chlorophyll b and Carotenoids (mg/100g) were detected and also, the antioxidant activity, total phenols, total flavonoids and ascorbic acid of aqueous extract of mint leaves have been evaluated. The highest content of chlorophyll a, chlorophyll b, total chlorophyll and content of carotenoids in the dried mint leaves was observed in irradiated samples with 20 kGy. While, the highest content was in the irradiated sample with 5 kGy. The data demonstrated that the irradiated dried mint leaves at 5, 10, 15 KGy had lower phenolic, flavonoids, total antioxidant and ascorbic acid compounds than non-irradiated control in the mint extract. While, irradiated mint at 20 kGy had higher phenolic compounds. It was found significant differences in the content of chlorophyll (a), chlorophyll (b), phenol, flavonoids, antioxidants, ascorbic acid, while there was no significant difference in the carotene content. By using of irradiation with gamma rays of 20 kGy, the most influencing was the higher content of chlorophyll (a) and chlorophyll (b). While the use of the level of irradiation with gamma rays of 15 kGy had a greater impact on the high content of carotene, phenol, flavonoids. Also, the use of irradiation at 10 kGy levels had the best effect on the high content of antioxidant and ascorbic acid. This study indicated the Gamma irradiation of dried peppermint leaves may lead to improved quality of oil.