Extraction of fumonisins B1, and B2 from white rice flour and their stability in white rice flour, cornstarch, cornmeal, and glucose

To extract fumonisin B-1 (FB1) and fumonisin B-2 (FB2) from Thai white rice flour, different solvent mixtures, temperatures, pH values, and addition of enzymes or ethylenediaminetetraacetic acid disodium salt (Na(2)EDTA) were examined. Three extractions with 0.1 M Na(2)EDTA achieved the highest recoveries. Initial recoveries of fumonisins added to white rice flour, cornstarch, cornmeal, and glucose varied with commodity. Funonisins disappeared in Thai white rice flour after 12 h. but 55% remained in another white rice flour. With cornstarch 20-30% fumonisins remained after 24 h: only 43% of C-14-labeled FB1 materials extracted from cornstarch was eluted with methanol from an immunoaffinity column. Fumonisins were stable in cornmeal for 24 h but only similar to50% remained after 30 days. With glucose, 25% of FB1 and FB2 remained 24 h after addition: N-(1-deoxy-D-fructos-1-yl)FB1 and N-(carboxymethyl)FB1 were detected in lower amounts than residual FB1 after 3 months.