DEGRADATION OF OAT SAPONINS DURING HEAT PROCESSING - EFFECT OF PH, STAINLESS-STEEL, AND IRON AT DIFFERENT TEMPERATURES

To understand the fate of oat saponins during processing, isolated ave nacosides A and B were heated at 100 and 140 degrees C at different pH . The catalytic effect of soluble iron complexes and stainless steel w as also examined. The avenacosides were stable when heated up to 100 d egrees C for 3 h at pH 4-7. Heating at 140 degrees C, especially at pH 4, led to partial destruction of the oat saponins. A degradation prod uct was detected and identified by mass spectrometry as desrhamnoavena cosides A and B. Addition of catalytic amounts of iron and stainless s teel dramatically increased the rate of saponin breakdown at pH 4-6. T his could in part explain the reduction of the saponin content in cann ed and roller-dried products.