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/degrees 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 degrees 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. (C) 2009 Elsevier Ltd. All rights reserved.