RESUMEN
Thiamin and riboflavin content of 15 varieties of rice processed in Guandong province in 3 different milling degrees (unpolished, standard and top grade) were estimated fluorospectrophotometrically. The thiamin content was averaged 0.48?0.01mg/100g for unpolished rice,0.33?0.07mg/100g for standard second grade and 0.16?0.04 mg/100g for top grade rice. The riboflivin content was averaged 0.09 ?0.02mg/100g for unpolished, 0.07?0.01mg/100g for standard second grade and 0.05 ?0.01mg/100g for top grade rice. Rice from Cing Er Ai, Min Ke Zhati, Qi Gui Zhao, Za You, and Zhong Gui rich in thiamin and the mixed third class rice from Shangshui county was rich in riboflaflavin. Rice from both Zhong Gui and Qi Gui Zhao was rich in thiamin and riboflivin. The thiamin and riboflavin content in rice depended on the rice variety and the area where rice was grown. The thiamin content in rice from Nan Hai County was higher than that from Shangshui and Guao Yiao Counties.Certain amount of thiamin and riboflavin was lost in the same kind of rice with diffeererit millig degrees. As compared with unpolished rice, the standard second grade rice lost about 30.63% of thiamin, 22.36% of riboflavin and the top grade rice lost 65.35% and 45.00% respectively.There was some thiamin and riboflavin loss during different storage periods, 4.85% of thiamin, 4.23% of riboflavin were lost after 6 months storage, and 10.3% of thiamin, 7.04% of riboflavin lost after one year storage.In order to improve the nutrition status of the people, it is necessary to advocate people to consume fresh and standard grade rice and to encourage cultivators to grow crops rich in nutrients.