Minimally processed papaya by vacuum osmotic dehydration (VOD) techniques / Papaya mínimamente procesada mediante técnicas de deshidratación osmótica al vacío (VOD)

The application of vacuum osmotic impregnation at constant temperature (25 °C) to obtain high moisture minimally processed papaya was evaluated. The fruit effective porosity was determined employing vacuum impregnation in isotonic sucrose solutions, obtaining values of around 3.4%. The fruit was submitted to vacuum osmotic dehydration (VOD) processes (60 mbar) in 60 °Brix sucrose syrups to depress a w from 0.99 to 0.98 (or less), always having a greater effectiveness than in the case of osmotic dehydration (OD) processes at atmospheric pressure. The use of a VOD initial process for different times, followed by the application of OD (called pulsed vacuum osmotic dehydration, PVOD, processes) had a greater effectiveness in depressing the a w than when only OD was applied in pro cesses up to 240 min. The pH reduction due to the addition of citric acid (2.5, 5.0 and 7.5%) to the sucrose syrup was more effective when applying VOD or PVOD processes. Minimally processed papaya ( a w 0.98, pH 3.5) could be obtained by applying VOD for only 10 min if the sucrose syrup had a citric acid concentration of 7.5%, or PVOD processes (VOD < 15 min and then OD < 45 min), em ploying concentrations of 2.5 and 5.0% of acid in the syrup.