Variations in physicochemical properties of brown rice (Oryza sativa L.) during storage

Abstract

Present study deals with variations of physicochemicals including γ-aminobutyric acid (GABA), γ-oryzanol, free sugar, lipoxygenase activity, fat acidity, and germination rate from Korean brown rice cultivars. With increase of storage time and temperature, GABA, γ-oryzanol, lipoxygenase activity, and fat acidity increased, whereas free sugar and germination rate was reduced. Among cultivars, 'Gopumbyeo' exhibited the highest contents in GABA and γ-oryzanol during 12 weeks storage at 25°C (GABA: 28.6±5.6→170.4±4.6 mg/100 g, γ-oryzanol: 6.1±0.7→6.7±0.4 mg/g) and 'Ilpumbyeo' significantly decreased in free sugar during 12 weeks storage at 10°C (1,423.7→1,058.4 mg/100 g). Moreover, 'Taebongbyeo' exhibited the highest quality owing to low lipoxygenase activity, low fat acidity, and high germination rate. In free sugar compositions, sucrose exhibited the highest content (>70%), followed by fructose (>7%), raffinose (>5%), glucose (>3%), and maltose (>2%) during storage. Based on our results, changes of physicochemicals in stored brown rice may be important information in processing food and functional properties. ? The Korean Society of Food Science and Technology.