Grain Quality of a Black Rice Variety ‘Pareunsuperjami’
A black rice variety ‘Pareunsuperjami’ developed from a conventional breeding method is an early maturing variety, of which heading time is 113 days after sowing, about the 30th of July. Its culm length and 1000 grain weights are 64.6 cm and 18.6 g, respectively, with the heavier grain weight than that of Heugjinju. ‘Pareunsuperjami’ has the higher content of cyaniding 3-glucoside (C3G) and strong antioxidant activity, compared to other color rice varieties. The highest content of total polyphenol extracted by a 70% of ethanol was found in the grain of Pareunsuperjami rice among other varieties, such as Daeripjami, Heugjinju, Daeripbyeo. The flavonoid and C3G contents were in the order of Pareunsuperjami > Daeripjami > Heugjinju > Daeripbyeo with a 5-fold higher C3G in Pareunsuperjami (1,038 mg/100g) than that of Heugjinju (204 mg/100g). The highest radical scavenging activity of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid, ABTS) was observed in the grain of Pareunsuperjami rice, about 383. The highest ascorbic acid equivalent antioxidant capacity (AEAC) was also observed in the grain of Pareunsuperjami (383), followed by Daeripjami (356) and Heugjinju (275). The highest DPPH radical scavenging activity in vitro was also found in the grain of Pareunsuperjami. The higher hydroxyl radical scavenging activity was also found in the grain of Pareunsuperjami than that of Daeripbyeo with no significant difference than other color rice varieties. These results suggest that there is a close relation between high content of C3G and strong antioxidant activity, and thus the Pareunsuperjami is a good source of natural antioxidants as a functional staple food.