Arsenic removal from rice by washing and cooking with water

Two Hungarian and one Chinese rice samples were selected in order to establish the extractable arsenic content by washing and cooking in water in a ratio of 6: 1, water:rice (cm 3 :g) by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). Total arsenic concentration of the Zhenshan 97, Risabell and Korostaj-333 samples were 171.3 +/- 7.1 ng g(-1), 116.0 +/- 13.7 ng g(-1) and 139.0 +/- 6.1 ng g(-1), respectively, which did not exceed the toxic limits established for As in Hungary (0.3 mu g g(-1)) or in China (0.7 mu g g(-1)). The predominant chemical form of As in the raw rice samples determined by on-line high performance liquid chromatography and ICP-MS was arsenite. Moreover, enzymatic hydrolysis with alpha-amylase + protease and microprobe focused sonication proved that arsenite could be removed in the highest extent by washing and cooking, meanwhile the main As form remaining in the cooked rice was As(V). Thus, it is recommended to prepare rice-containing dishes in abundant water, which should be discarded after washing and cooking. The results were validated with a NIST SRM 1568a. (C) 2007 Elsevier Ltd. All rights reserved.