The application of high hydrostatic pressure for the stabilization of functional foods: pomegranate juice

The paper aims at investigating the potential application of non-thermal innovative technologies, such as high hydrostatic pressure, for the sanitization of functional liquid foodstuffs. A 100% pomegranate juice was selected for the experiments, due to its high bioactive compounds content. The operating pressure, temperature and holding times at the pressure set point were changed over a wide range, with the aim of optimizing the processing condition in order to assure the microbiological stability of the processed juice as well as preserve the natural content of the functional compounds. The experiments clearly demonstrate that the high pressure treatment at room temperature improves the quality of pomegranate juice, increasing the intensity of red color of the fresh juice and preserving the content of natural anthocyanins. The residual activity of some enzymes at the end of high pressure processing, independently on the processing conditions, such as the polyphenoloxidase (PPO), causes the degradation of the nutraceutical compounds as observed in particular processing conditions, thus suggesting that the optimal combination of the processing parameters should take into account the degradation of the anthocyanins as well as the enzymatic activity.