Pressure and temperature combination for inactivation of soymilk trypsin inhibitors

High hydrostatic pressure (HHP) processing, an emerging technology for food preservation, in combination with thermal treatment (250/50, 550/19, 550/65, and 550/80 MPa/°C) was applied to soymilk made from previously soaked soybeans (in distilled water or 0.5% sodium bicarbonate solution). First order kinetics constants ranging from 0.081 to 0.217 min-1, for residual trypsin, were estimated in soymilk from soaked soybeans at selected pressure-temperature combinations. Residual trypsin, at 550 MPa and 80 °C, was high at higher HHP holding times. The highest percentage of residual trypsin (76%) was estimated after a 15 min holding time. The use of sodium bicarbonate for soaking of soybeans synergistically decreased the trypsin inhibitor activity in soymilk in comparison with residual trypsin using distilled water alone. © 2009 Elsevier Ltd. All rights reserved