Assessment of texture and storage conditions of mangoes slices dried by a conductive multi-flash process

摘要

Glass transition temperature (T-g) and sorption isotherms can be used to establish state diagrams that help to assess storage conditions to keep the food as an amorphous material in a glassy state. In this study, state diagrams and mechanical properties were assessed to predict the storage conditions of mangoes dried by 1) air-drying; 2) freeze-drying; 3) vacuum-drying and 4) conductive multi-flash drying (KMFD - four cycles of heating/vacuum pulse followed by vacuum-drying). Dried mangoes showed a typical sorption isotherm behavior of hygroscopic materials. In the relative humidity (RH) range investigated (between 11.3% and 90.3%), T-g of processed samples decreased from 44 degrees C to -68 degrees C, due to the plasticizing effect of water. Dried mangoes stayed structurally stable at room temperature (25 degrees C) if storage RH was kept at 25%, in this conditions the moisture content was 0.036 g g(-1) (d.b.). The puncture tests results confirmed that, at room temperature, samples stored at RH higher than 30% lost their crispness.