Autores UPV
Paniagua Martínez Ingrid,
Castillo Zamudio Rosa Isela,
Ortuño Cases Carmen,
García Alvarado Miguel Ángel,
Benedito Fort José Javier
Abstract
Supercritical carbon dioxide (SC-CO2) inactivation technology represents a
promising non-thermal processing method, as it promotes minimum impact on
the nutritional food properties. However, in some cases high pressures or
temperatures and too long treatment times are required to guarantee the foods
safety. In order to obtain the required lethality at shorter processing times, a
combination of SC-CO2 with high power ultrasound (HPU) has been studied.
The results showed that the combination of both techniques in a batch system
accelerated the death of E. coli compared with the use of only SC-CO2. The
objective of this work was to study the combined effect of SC-CO2 and HPU on
E. coli inoculated in commercial apple juice, approximately 108 CFU and treated
in a continuous system. The influence of the pressure, temperature and
retention time on the inactivation process was evaluated. Experiments were
performed at different temperatures (31, 36 and 41 °C), pressures (100-200 bar)
and retention times (1.72, 2.58 and 5.44 min).The application of HPU
significantly (p<0.05) influenced the inactivation rate. Using SC-CO2 (100 bar, 31
ºC) for 2.58 min was required to achieve 3.29 log-cycles of reduction while using
SC-CO2+HPU (100 bar, 31 ºC, 2.58 min), a reduction of 7.42 log-cycles was
obtained. The inactivation rate of E. coli increased as pressure and retention
time increased during the SC-CO2 +HPU treatments, at 31 ºC and 100 bar a
reduction of 8 log-cycles was achieved at 5.44 min compared with only 4.4 logcycles
obtained at 1.79 min. No significant (p<0.05) effect of temperature was
found at the different process conditions. The results demonstrated the potential
of the continuous SC-CO2 +HPU inactivation technique, the use of mild process
conditions could lead to an increase in the quality of the product treated under
this technique.
