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

Abstract

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 aw 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 ( aw 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.