Determination of Selenium Concentration of Rice in China and Effect of Fertilization of Selenite and Selenate on Selenium Content of Rice

A method of hydride generation atomic fluorescence spectrometry was applied to the determination of the selenium concentration of regular polished rice in China and selenium-enriched polished rice obtained by foliar application of selenium-enriched fertilizer in the forms of selenite and selenate. The average selenium content of regular rice was 0.025 ± 0.011 μg g-1. On the basis of a daily dietary rice intake of 300−500 g suggested by the China Nutrition Society, the total selenium intake from regular rice was calculated to be 7.5−12.5 μg per person per day for an adult. The selenium contents of rice were significantly increased to 0.471−0.640 μg g-1 by foliar application of selenium-enriched fertilizer at rate of 20 g of Se ha-1 in the forms of sodium selenite and sodium selenate. The selenium content of rice by application of a fertilizer of selenate was 35.9% higher than that by a fertilizer of selenite, which showed that Se-enriched fertilizer in selenate exhibited greater efficiency in increasing Se content in rice products. The Se-enriched rice products can increase daily Se intake on average by 100−200 μg of Se per day by the consumption of 400 g of rice products if the Se level of rice products is controlled at 0.3−0.5 μg of Se g-1. Because rice is a staple food in China, selenium-enriched rice obtained by bioenrichment of selenium to increase the Se content of rice could be a good selenium source for the population in selenium-deficient regions. Keywords: Rice; selenium content; daily dietary selenium intake; selenium-enriched rice