KINETICS OF ASEPTIC CONCENTRATED ORANGE JUICE QUALITY CHANGES DURING COMMERCIAL PROCESSING AND STORAGE

Aseptically concentrated orange juice (COJ) was processed commercially at three holding temperatures (84, 87 and 90 degrees C, 72 s) and stored for up to 7 weeks at 32 degrees C and 15 weeks at 22 degrees C. No differences were found in nonenzymic browning (NEB), vitamin C, sucrose, fructose and glucose, furfural, HMF (5-hydroxymethyl furfural), and DMHF (2,5-dimethyl-4-hydroxy-3(2H)-furanon) concentrations due to the different thermal treatment. The dominating factors affecting vitamin C retention and NEB were time and storage temperature. A lag-time was observed in NEB formation and its length depended on storage temperature. Furfural concentration was below 1 ppm. HMF reached c. 11 ppm after 7 weeks at 32 degrees C. DMHF concentration decreased throughout the storage period. Sensory evaluation showed a nonsignificant preference for COJ processed at the lower temperature.