Soybean Heat-treated using a Fluidized Bed

The fluidized bed technique was evaluated for treating soybeans with two purposes: drying and inactivation of heat-labile inhibitors. The effect of air temperature, soybean initial moisture and treatment time on moisture, urease activity, trypsin inhibitor activity and available lysine were determined. No inactivation was detected at 100 °C at any initial moisture content, while at 110 °C and any initial moisture level drying occurred before inactivation. At 120, 130 and 140 °C inactivation was produced before drying at 175 and 235 g/kg water content. At these temperatures, no significant losses of available lysine were detected. Consequently, soybean drying and inactivation can be performed in a single step, while maintaining nutritional value.