The aim of the present study was to evaluate the effect high hydrostatic pressure (HHP) processing (350–
550 MPa for 30, 90 and 150 s) on microbial quality as well as physico-chemical and bioactive compounds
of pomegranate juices during 35 days of storage at 4 °C. Antioxidant activity, phenolic content and color
values (L*, a* and ΔE) were determined. The microbiological results showed that HHP-treatment at or over
350 MPa for 150 s resulted in a reduction of the microbial load around 4.0 log cycles, and were sufficient to
keep microbial populations investigated below the detection limit during the whole storage period. Therefore,
these treatments were able to extend the microbiological shelf-life of pomegranate juice stored at 4 °
C for more than 35 days. All HHP-treated samples showed a slight reduction in antioxidant capacity during
storage time. Phenolic content increased significantly (pb0.05) between 3.38% and 11.99% for treated samples
with 350 MPa and 550 MPa at day 0. The ΔE values, which are an indicator of total color difference,
showed that there were significant differences (pb0.05) in color between untreated and treated samples
and showed a significant decrease (pb0.05) in ΔE values during storage time. The highest color difference
was obtained at day 35 for 550 MPa for 90 s. These results clearly demonstrate that the color stability of
pomegranate juice depends on the processing conditions. During the first 15 days, the pH, °Brix and titratable
acid were not significantly affected by high pressure processing.
Industrial relevance: This paper provides information of storage stability of pomegranate juice after pressure
treatments which is quite scarce. In database collected, criteria for commercial production of high quality
pomegranate juice with safety requirements could be established.
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