Potential mechanism involved in removal of hydrophobic pesticides from vegetables by hydrostatic pressure

In our previous study, we found that the removal rate of hydrophobic pesticide on cherry tomatoes shows the maximum by hydrostatic pressure treatment (HPT) around 75 MPa. The objective of this study was to investigate the causes of reduction in the removal rate above 75 MPa HPT. Separating cuticle from flesh of the cherry tomatoes after HPT and examining the pesticide residues in each part the following was found: the detectable pesticide amount in the flesh part showed little change from the non-treated samples. Ethanol was applied as the surrounding solution during pressurization so as to prevent the reattachment of pesticide and decrease water solubility, and removal efficiency declined little. The effect of HPT on removal rate time indicated no significant difference at 0.1 MPa, the optimum level to be at 75 MPa for a comparatively short time, and at 400 MPa removal rate increased with time.