GLASS TRANSITION PHENOMENON ON THE KINETIC OF ASCORBIC ACID DEGRADATION OF PAPAYA (Carica papaya L.) DURING CONVECTIVE DRYING

摘要

The aim of this work was to study ascorbic acid degradation during hot air drying of papaya and to verify its relationship with glass transition.The experiments were carried out at air temperatures between 40-70°C.Higher retentions were observed at lower temperatures.At 70°C,papaya was in a rubbery state,characterized by great molecular mobility inside the food,which facilitates the reactions of degradation,and remained so until the end of process.At 40°C,the rate of degradation of nutrient became very slow at moisture content of 0.2g/g,which coincided with phase transition of papaya from rubbery to glassy state.