High pressure stabilization of orange juice: Evaluation of the effects of process conditions

A laboratory scale apparatus was designed, set up and tested to investigate the effects of high hydrostatic pressure on the stabilization of orange juice, whose quality is dramatically reduced by the classical thermal preservation processes used in the food industry. An evaluation of the microbial activity as well as of the chemical composition of orange juices processed at different pressure levels and operating times was conducted and compared with that of fresh juice. The overall quality of the orange juice processed at high pressure was excellent and the refrigerated shelf life was not less than two months, provided that a minimum pressure level of 3500 bar (process time 1 min and temperature 30 degrees C) was attained.