Changes were observed when the color characteristics were analyzed
by colorimetric during the storage period. There was a significant
(pb0.05) effect of pressure on color characteristics of pomegranate
juice (Fig. 3) with increased pressure, samples become brighter (higher
L* values), and less red (lower a* values) at day 0. Although 350MPa
pressure reduced a* values significantly when comparing with 450
and 550 MPa for day 0, the difference was still significantly higher
when compared with the control. The increased pressure also increased
b* value (yellowness) of samples. However, a significant decrease
(pb0.05) in the lightness (L* value)was detected for those juices stored
for 35 days at 4 °C compared to day 0 for treated sampleswith high hydrostatic
pressure. A considerable decrease of a* values was observed
after storage of juices at day 35 for treated samples at 350MPa and
450 MPa for 30 s compared with day 0. Instead the samples treated at
450 MPa for 90 s, 150 s and 550MPa showed an increase in a* values.
These decrease of a* and L* values can be attributed to the degradation
or polymerization of anthocyanins and indicate a fading of the typical
red color of pomegranate juice. Pérez-Vicente, Serrano, Abellán, and