Supercritical carbon dioxide processing for food, biomedical and environmental applications

The growing demand for safe, high-quality, and sustainable products requires the development of innovative processing technologies that minimize thermal and chemical loads while ensuring efficiency and environmental responsibility. This doctoral research explores the potential of carbon dioxide (CO2) as a green processing agent across food, biomedical, and environmental applications. The work is structured around five main research contributions. First, the mechanisms of microbial inactivation by supercritical CO2 (scCO2) were critically reviewed, with particular emphasis on sublethal injury, viable-but-non-culturable (VBNC) states, and the potential of hurdle technologies such as pulsed electric fields, ultrasound, and high-pressure processing. This theoretical foundation supports the experimental and technological developments presented in the subsequent chapters. Second, predictive models for CO2 solubility in fruit and vegetable juices were developed and validated. Using factorial design of experiments and regression analysis, solubility was correlated with key compositional and process variables, and the models were successfully applied to commercial juices. These results provide practical tools for optimizing scCO2 pasteurization processes in complex liquid matrices. Third, a novel in-package scCO2 technology (HPMAP⁺) was designed and tested. By integrating a valve-assisted system into packaging materials, the limitations of traditional pouch-based processes were overcome. Microbial inactivation trials demonstrated the feasibility of the approach and its potential applicability to both food preservation and biomedical sterilization. Fourth, the environmental potential of CO2 fixation was investigated through solubility and kinetic studies on dissolved calcium carbonate systems. The modeling of carbonate dissolution and transformation offers insights into sustainable CO2 utilization routes, including the production of carbonates for the glass industry. Finally, methodological advances were demonstrated through the development of novel texture analysis descriptors for cheese stretchability, applied to both dairy and plant-based products. This case study highlights how advanced analytical tools can bridge food structure characterization and processing innovation. Overall, the thesis provides new scientific understanding, predictive models, and technological solutions that advance CO2-based processing. By integrating perspectives from food, biomedical, and environmental engineering, the research contributes to the transition toward safe, efficient, and sustainable industrial processes.