Impact of high hydrostatic pressure (HHP) pre-treatment drying cashew (Anacardium occidentale L.): drying behavior and kinetic of ultrasound-assisted extraction of total phenolics compounds

This aim of this study was aimed to evaluate the impact of HHP (high hydrostatic pressure) pre-treatment on the drying behavior of cashew slices, water adsorption isotherms, on extraction kinetic of total phenolic compounds (TPC) and antioxidant activity (AA). The drying kinetics were performed for cashew slices without pre-treatment (control) and pre-treated with 200 MPa (HHP1), 350 MPa (HHP2) and 500 MPa (HHP3) at a temperature of 70 degrees C in an electric oven (1200 W). Drying kinetics experimental data were fitted using empirical and diffusive models (third type boundary condition). The kinetics of ultrasound-assisted (40 kHz and 132 W) extraction of total phenolic compounds (TPCs) were realized and was determined AA (ABTS center dot +, DPPH center dot and FRAP) and water adsorption isotherms. The application of pressure 500 MPa (HHP3) provided an increase in the moisture transport process, a higher drying rate and shorter process time (40%). The effective diffusivity ranged from 1.2546 x10(-8) m(2) min(-1) (control) to 3.2045 x10(-8) m(2) min(-1) (HHP3). The extraction of TPC he was higher in the time of 180 min, emphasis for HHP3 who presented 154.48 mg GAE 100 g(-1). Higher retention percentages AA by the three methods were observed for the slices pre-treated (HHP3) and the adsorption isotherms which presented characteristic of the type II curves. Therefore, the results of this study provide information for the potential application of HHP as a drying pre- treatment. [GRAPHICS] .