Characteristic Changes in Brown Rice (Oryza sativa L.) Cultivars of 3 Ecotypes During Different Storage Conditions

The aim of this study investigated the fluctuations of 3 characters from 3 ecotypes [early ripening (ER), middle ripening (MR), and late ripening (LR)] of 20 Korean brown rice cultivars in different storage systems [time: 12 and 24 weeks, temperature: low (10 degrees C) and room (25 degrees C)]. With increase of storage time and temperature, lipoxygerlase activity, and fat acidity increased, whereas gemlination rate was reduced. ER cultivars exhibited the highest lipoxygenase activity of 35.49 +/- 2.46 unit/ing protein during 24 weeks storage at 25 degrees C, followed by LR (32.73 +/- 1.33) and MR (32.66 +/- 1.62) cultivars. The amounts of fat acidity also were observed by the same order (ER: 20.40 +/- 2.12>LR: 19.68 +/- 1.86>MR: 19.64 +/- 1.35 mg KOH/100 g). Germination rate slightly decreased with increase of time and temperature (MR>LR>ER), but MR and LR cultivars showed the most significant changes (ER: 60.90 +/- 23.47%, MR: 32.66 +/- 13.95%, and LR: 32.53 +/- 5.87%). On the basis of above results, MR cultivars were evaluated the highest quality, because high lipoxygenase activity, high fat acidity, and low germination rate have deteriorated in quality and generated off-odor. Thus, MR cultivars might be very important sources in food processing and stored dietary supplement aspects.