Heat stability of zearalenone in an aqueous buffered model system.

Zearalenone is an endocrine disruptor with estrogenic activity, produced primarily by Fusarium graminearum, a common cause of corn ear rot and Fusarium head blight or scab in wheat. Zearalenone can be a contaminant of both corn and wheat and may survive thermal food processes. This study was done to determine the heat stability of zearalenone. Reduction of zearalenone was measured during heating at different temperatures (100, 125, 150, 175, 200, and 225 degrees C) in an aqueous buffer solution at different pH values. The rate and extent of zearalenone reduction increased with processing temperature. Less than 23% of zearalenone was lost when heated to </=125 degrees C whereas 34-68% was lost at 150 degrees C after 60 min, depending on the pH of the buffer. Greater than 92% of zearalenone was lost after 60 min when heated to >/=175 degrees C, and complete reduction of zearalenone was observed in less than 30 min at 225 degrees C, regardless of pH. Overall, zearalenone was most stable at pH 7 followed by that at pH 4 and 10, and the greatest losses occurred above 175 degrees C.