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 (Fig. 3). In general, the ΔEwas significantly
higher in treated samples at 350, 450 and 550 MPa compared
to control sample at day 0. The ΔE values of untreated samples did not
show significant difference (p>0.05) during storage (35 days) but treated
samples with high hydrostatic pressure showed a significant decrease
(pb0.05) in ΔE values during storage time and 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. Ferrari et al. (2010) working with
pomegranate juices reported that levels of pressure higher than
500 MPa have important variations as to brown color. The color compounds
of HHP processed fruits and vegetables change during storage
due to incomplete inactivation of enzymes and microorganisms (Oey,
Van der Plancken, Van Loey, & Hendrickx, 2008); however, Perera et al.
(2009) reported that HHP treatments produce a minimal effect in color
changes in fruit products.