Pigmented rice oil: Changes in oxidative stability and bioactive compounds during storage of whole grains

This study evaluated the effects of storage temperature on the oxidative stability and bioactive compounds present in oil extracted from whole rice grains. Whole rice grains (brown, black, and red pericarps) were stored at temperatures of 16, 24, 32, and 40 degrees C for 6 months. Oil extraction was carried out on samples at the beginning, and after 6 months, of storage. Oil acidity, extinction coefficients (K-232 and K-270), fatty acid profiles, -oryzanol, carotenoid, and tocopherol contents were evaluated. Oil extracted from rice grains with black pericarps showed the highest concentrations of -oryzanol, carotenoids, and tocopherols, followed by oil extracted from grains with brown and red pericarps. A storage temperature of 16 degrees C was effective for maintaining good oil quality and bioactive compounds extracted from the oil when stored for 6 months. Practical applicationThe consumption of nutraceutical and bioactive foods has gained importance in recent years, highlighting the use of whole pigmented rice grains. A great amount of the rice grains used in the world's food industry are stored for periods up to 12 months prior to their use. This study presents the changes in the quality of oil and bioactive compounds present in the oil extracted from rice grain with brown, black and red pericarp as a function of storage conditions during long-term and may help food industries to elucidate the differences in quality of oil and bioactive compounds in rice oil. The proper handling of post-harvest rice grains is important to increase economic gains for the processing industries and maintain the quality of oil for human consumption and industrial use.