Non-thermal microbial inactivation by using supercritical carbon dioxide: Synergic effect of process parameters

• Published in: The Journal of supercritical fluids 2018-09, Vol.139, p.97-104
• Main Authors: Silva, Eric Keven, Alvarenga, Verônica O., Bargas, Matheus A., Sant'Ana, Anderson S., Meireles, M. Angela A.
• Format: Article
• Language: English
• Subjects: Apple juice; Emerging technology; Lactobacillus casei; Supercritical fluid
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2018.05.013

[Display omitted] •Supercritical technology was employed as a non-thermal process for the inactivation of L. casei.•A homemade experimental apparatus for food processing was validated.•At 15 MPa, 55 °C, 30 min and a 70% CO2 volume, a reduction of more than 6 log cycles occurred.•A mathematical model for the microbial inactivation was proposed and validated. In this study, we evaluated the influence of CO2 volume ratio (%) and its synergic effect with the pressure (MPa), temperature (°C) and process time (min) on the inactivation of Lactobacillus casei cells inoculated in apple juice (107 CFU/mL). The effects of process variables on the logarithmic reduction of L. casei cell counts were estimated by a two-level Plackett–Burman factorial design. A Box–Behnken design was subsequently employed to evaluate the interaction between the different factors on the supercritical microbial inactivation. The results showed that the process intensification led to a higher logarithmic reduction. Operating at 15 MPa, 55 °C, 30 min and a 70% CO2 volume ratio, the process was able to reduce L. casei cell counts by more than 6 log cycles. In addition, this work reports the validation of an experimental apparatus assembled by our research group for food processing by employing supercritical carbon dioxide.