BACKGROUND Selenium is an indispensable trace element for humans and its deficiency can lead to serious health complications. Nearly 70% of the area of China faces selenium deficiency. To deal with this problem, selenium‐enriched rice has been increasingly incorporated into everyday diets. However, there is a lack of in‐depth studies of the absorption, translocation, and transformation of selenium in the different parts of the rice plant when sprayed with sodium selenite. RESULTS Foliar sodium selenite applied at critical growth stages can significantly improve the total and organic selenium content of plants. Application of 10 mg L−1 sodium selenite led to the most organic selenium (0.03 mg kg−1) in polished rice. Correlation studies of sodium selenite applied to leaves and other plant parts showed that total selenium accumulated most in glume, followed by rice bran, then polished rice, and finally embryo. The behavior of organic selenium was different. Organic selenium accumulated most in polished rice, then embryo, then rice bran, and finally glume. Moreover, 75–85% of the Se found in polished rice and embryo was organic in nature. CONCLUSIONS We propose that 10 mg L−1 sodium selenite can be recommended as appropriate for foliar fertilization in the organic selenium biofortification of Se‐free rice. © 2018 Society of Chemical Industry

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Using HPLC, it was demonstrated that the major free phenolic compound in the pericarp and seed coat of red rice was cyanidin, which belong to anthocyanidin glucoside, exist only in the episperm of red rice as content of 1.64±0.10 mg/g. Anthocyanidin glucoside play a significant role in eliminating free radicals and reacting oxygen species (ROS) to prevent cellular oxidative stress. However, the chemical stability of anthocyanidin glucoside has been one of the major drawbacks for health applications. For longer storage, our results showed that red rice anthocyanidin glucoside could be stored with 0.3 % Vitamin C or 0.5 % NaHSO 3 , and be protected from light, high temperature, high pH and metal ions in environment. Antioxidant activity verified that anthocyanidin glucoside performed better than Vitamin C in ferrous ions chelating activity, scavenging activities for hydroxyl and DPPH radicals. Overall, the red rice might be used as a natural antioxidant supplement applying medical treatments in future days.