Fig. 4 shows the freezing curves of fresh samples and each
cryoconcentration cycle from blueberry and pineapple juices. Both
juices (blueberry and pineapple) show a clear effect of solute concentration,
with an important difference in the freezing plateau between fresh
sample and cryoconcentrates, and an expected effect of lowering
the freezing temperature as the cryoconcentration cycles increase.
About the freezing rate, samples of fresh juice have a rate of about
0.2 mm min−1
, whereas the cryoconcentrate samples increase to values
around 0.3 to 0.4 mm min−1
. These values show (based on freezing
front propagation) moderate freezing rates (Ramaswamy & Marcotte,
2006).