water content of this fruit. By increasing the number of cycles, solids
content in the concentrated fraction increased quasi-linearly with a
correlation coefficient R2 = 0.9966, and reached values of about 20, 26
and 33 °Brix at the first, second and third cryoconcentration cycles, respectively;
reach after the third cycle an increase of approximately 2.5
times the initial concentrations of solids. Amount of solutes entrapped
in the separated ice fraction has been estimated at 2 and 12 °Brix at
the first and second cryoconcentration cycles, respectively. In the third
cycle, overall process efficiency decreased, and the solutes in the ice
fraction increased up to 15 °Brix (Fig. 5a). In the cryoconcentration
from a pineapple juice (Fig. 5b) a similar behavior is observed, and
solute content in the concentrated fraction increased quasi-linearly
with a correlation coefficient R2 = 0.9975, and reached values of
about 32 °Brix at the third cryoconcentration cycle. This value is lower
than that achieved by Bonilla-Zavaleta et al. (2006), which was close
to 41 °Brix from 12 °Brix pineapple juice, frozen at −20 °C and centrifuge
by cycles using centrifuge tubes much wider (8 cm long × 8 cm
wide) than the present study, so possible that under these conditions
a frozen concentrate radial stratification occurs, causing a better separation
of the solutes by centrifugation because the ice would be more
concentrated toward the surface of the centrifuge tubes (Bakal &
Hayakawa, 1973). The evolution over the cryoconcentration cycles
from both fruit juices was expected, because similar behavior was
water content of this fruit. By increasing the number of cycles, solidscontent in the concentrated fraction increased quasi-linearly with acorrelation coefficient R2 = 0.9966, and reached values of about 20, 26and 33 °Brix at the first, second and third cryoconcentration cycles, respectively;reach after the third cycle an increase of approximately 2.5times the initial concentrations of solids. Amount of solutes entrappedin the separated ice fraction has been estimated at 2 and 12 °Brix atthe first and second cryoconcentration cycles, respectively. In the thirdcycle, overall process efficiency decreased, and the solutes in the icefraction increased up to 15 °Brix (Fig. 5a). In the cryoconcentrationfrom a pineapple juice (Fig. 5b) a similar behavior is observed, andsolute content in the concentrated fraction increased quasi-linearlywith a correlation coefficient R2 = 0.9975, and reached values ofabout 32 °Brix at the third cryoconcentration cycle. This value is lowerthan that achieved by Bonilla-Zavaleta et al. (2006), which was closeto 41 °Brix from 12 °Brix pineapple juice, frozen at −20 °C and centrifugeby cycles using centrifuge tubes much wider (8 cm long × 8 cmwide) than the present study, so possible that under these conditionsa frozen concentrate radial stratification occurs, causing a better separationof the solutes by centrifugation because the ice would be moreconcentrated toward the surface of the centrifuge tubes (Bakal &Hayakawa, 1973). The evolution over the cryoconcentration cyclesfrom both fruit juices was expected, because similar behavior was
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