Enhancement of antioxidative potential of mung bean by oxygen plasma irradiation of seeds

The present study aimed to assess the effect of oxygen plasma treatment on the germination rate, growth, and antioxidative activity of mung beans at different pressures and irradiation exposure times. Oxygen plasma was capable of shortening the germination time as well as improving the germination rate at each gas pressure and exposure time compared to control. The germination rate of plasma-treated seeds exceeded 90% within 18 h of seeding compared to 30 h for the control (without plasma treatment). Stem length increased by 25.42 to 52.88% depending on the pressure and exposure time compared to control. Vitamin C content in the stem and root increased from 1.49 to 1.97 and 1.27 to 2.04-fold higher, respectively, depending on the pressure and exposure time compared to control; while in the case of thiol content, it was 1.16 to 2.76 and 1.09 to 2.49-fold higher in the stem and root, respectively. Plasma treatment increased antioxidant potency compared to control. Maximum antioxidant potency was found at 30-min exposure time, although the alterations in pressure did not elicit prominent changes. Plant growth, vitamin C and thiol contents, and antioxidant potency were increased with increasing pressure up to 60 Pa, which then declined with higher pressure. On the other hand, these parameters decreased with a longer exposure time, except for the antioxidants. Thiol and vitamin C contents were associated with plant growth.