Influence of thermal and dense-phase carbon dioxide pasteurization on physicochemical properties and flavor compounds in Hami melon juice.

The influence of thermal and dense-phase carbon dioxide (DP-CO(2)) pasteurization on physicochemical properties and flavor compounds in Hami melon juice was investigated. Melon juice was pasteurized using DP-CO(2) treatment and compared to a conventional high-temperature-short-time (HTST) method. The DP-CO(2) treatment was carried out using a DP-CO(2) unit (55 degrees C, 60 min, and 35 MPa). The thermal pasteurization was performed at 90 degrees C for 60 s with an adapted laboratory setup. Effects of variations to both treatments on pH and concentrations of microbes, beta-carotene, ascorbic acid, sugars, organic acids, and volatile compounds were investigated. The changes of pH and organic acid and sugar concentrations were not significant. There were significant differences between treatments in microbial count, vitamin C, beta-carotene, and volatile compound concentrations. In general, DP-CO(2) treatment had less of an effect on the measured variables than the thermal treatment.