INFLUENCE OF HIGH-PRESSURE BLANCHING ON POLYPHENOLOXIDASE ACTIVITY OF PEACH FRUITS AND ITS DRYING BEHAVIOR

摘要

Experiments were conducted to evaluate the feasibility of using high-pressure processing as an alternate for hot-water blanching of peach slices. Peach slices were pressure processed at various combinations of pressures (50-700 MPa) at 25℃ with and without citric acid for two holding times (5 and 10 min). Pressure treatment (>300 MPa), in combination with citric acid (1-1.2%), was an effective method to inactivatepeach polyphenoloxidase enzymes. Pressure-treated peach slices, with and without citric acid, were subsequently dehydrated in a cabinet dryer at 70℃. Pressure treatment enhanced the drying rate and reduced the drying time. Logarithmic model satisfactorily described the drying behavior of peach slices. Pressure-processed samples had higher moisture diffusivity than control samples. The results reveals that high-pressure processing of peach fruits suspended in citric acid medium can be used as potential alternative for hot water blanching.