EFFECT OF REFRIGERATED STORAGE ON THE QUALITY OF PAPAYA TREATED BY HIGH HYDROSTATIC PRESSURE

High pressure processing (HPP) of fruit slices followed by refrigerated storage is a new tool to preserve fresh-like processed fruits during weeks. Physical-chemical (pH, titratable acidity, soluble solids), physical (colour and firmness), chemical (vitamin C) and biochemical (PPO and POD enzymes) characteristics of papaya slices were analysed after high pressure processing (400 MPa/25 degrees C/l min) and during 20 days of refrigerated storage at 4 degrees C. Papaya slices pH (5.89) suffered a significant decrease (p<0.05) after HPP and during the refrigerated storage. The opposite happened with the titratable acidity. Soluble solids (degrees Brix) increased after HPP and remained unchanged during refrigerated storage. All colour parameters (a*, b* and L*) and firmness (N/g) changed significantly (p<0.05) after HPP but not during the refrigerated storage. Vitamin C extracted increased after EIPP and it did not show significant degradation during 20 days at 4 degrees C. Both quality related enzymes, PPO and POD, showed a significant decrease (p<0.05) after HPP and their activity was not detected after the sixth day of refrigerated storage.