Effect of high-pressure processing on carotenoids profile, colour, microbial and enzymatic stability of cloudy carrot juice.

The objective of this work was to assess the impact of high-pressure processing (HPP) on the carotenoid profile, colour as well as the microbial and enzymatic stability of cloudy carrot juice. The predominant carotenoids in the fresh juices were by far the provitamin A carotenoids β-carotene and α-carotene. Others were ζ-carotene, phytofluene, phytoene and lutein. HPP at 300 MPa in three cycles caused the highest carotenoids degradation (41%) whereas the lowest degradation (26%) was achieved at 600 MPa. The highest inactivation of POD (31%) and PPO (57%) was achieved with 600 MPa and 300 MPa applied in three cycles, respectively what indicates that POD is more responsible for carotenoids degradation. The colour differences (ΔE*ab) between fresh juice and HPP-treated juices ranged from 3.02 to 4.15 CIELAB units. As far as the impact on microorganism was concerned, there was a clear trend between the applied pressure and the microbial reduction achieved.