Effect of a different high pressure thermal processing compared to a traditional thermal treatment on a red flesh and peel plum purée

The effect of the application of different high pressure thermal (HPT) treatments on the instrumental color, the activity of the polyphenoloxidase (PPO) enzyme, bioactive compounds (total polyphenols and anthocyanins) content and the antioxidant activity were was evaluated after processing a red flesh and peel plum purée and compared to an equivalent thermal treatment (TT). Different pressure levels (300, 600, and 900MPa) at different initial processing temperatures (60, 70, and 80°C) were applied. HPT treatments produced a similar inactivation of the PPO as the TT (~ 50%). In addition, HPT treatment was more effective than the TT in preserving the original colour, the anthocyanins content and the antioxidant activity of the processed purées. The application of pressures at 600MPa combined with initial temperatures of 70°C was the treatment which gave the highest inactivation of the PPO and best maintained the bioactive compounds of purées.The exploration of new technologies, such as the combination of pressure and heating for short times (high pressure thermal or HPT treatments), could be a new way to extend the shelf-life of fruit-derived products. HPT treatments can better preserve bioactive compared to most traditional thermal treatment. While there are currently no HPT-processed shelf-stable foods commercially available, it's possible to provide a viable process for heat-sensitive products such as fruit-derived products that would suffer a severe loss of quality by the application of a traditional thermal process. A previous study (González-Cebrino et al., 2013) showed that high pressure processing (HPP) did not inactivate polyphenoloxidase enzyme in plum purée. Results of this paper could allow production of a plum purée with an enzyme activity similar to a thermally treated purée.