In a circular economy, products, waste, and resources are kept in the system as long as possible. This review aims to highlight the importance of cold plasma technology as an alternative solution to some challenges in the food chain, such as the extensive energy demand and the hazardous chemicals used. Atmospheric cold plasma can provide a rich source of reactive gas species such as radicals, excited neutrals, ions, free electrons, and UV light that can be efficiently used for sterilization and decontamination, degrading toxins, and pesticides. Atmospheric cold plasma can also improve the utilization of materials in agriculture and food processing, as well as convert waste into resources. The use of atmospheric cold plasma technology is not without challenges. The wide range of reactive gas species leads to many questions about their safety, active life, and environmental impact. Additionally, the associated regulatory approval process requires significant data demonstrating its efficacy. Cold plasma generation requires a specific reliable system, process control monitoring, scalability, and worker safety protections.

Inactivation of pectinmethylesterase (PME) and quality parameters of orange juice have been studied after high pressure carbon dioxide (HPCD) treatment. The HPCD treatment conditions covered a wide range of temperature from 2 to 40 °C, far below normal thermal treatment, while operating pressure was varied from 10 to 30 MPa and exposure time from 3 to 60 min. A decrease in PME activity was found, even at the lowest temperature studied in this work, 2 °C. Different inactivation kinetic models were used to correlate the PME residual activity: the two-fraction model, the fractional-conversion model and the Weibull model. The two-fraction model presents the lowest mean relative deviation. Some quality parameters such as colour, pH, ºBrix, turbidity, ascorbic acid, total acidity and particle size distribution (PSD) were also determined right after HPCD treatment and along storage at 4 °C up to 12 days. PSD shows that HPCD treatment results in a volume increase of small particles and a volume decrease of large particles regarding the non-treated orange juice. Calcium content was also determined before and after HPCD treatment to check for insoluble calcium carbonate formation but not significant changes were observed in calcium content after HPCD treatment.MINECO (CTQ2015-64396-R

The hydrolysis of the water-soluble protein (WSP) fraction from tuna fish meal was evaluated by subcritical water (subW) by using N₂ and CO₂ as different pressurization agents in the temperature range from 140 to 180 °C. For both gases, the amino group release increased by increasing working temperature while the Lowry response decreased due to production of smaller-size peptides and free amino acids. The free amino acid content was higher with CO₂ than with N₂. At 180 °C, 344 ± 5 and 275 ± 3 mg of free amino acids per g of WSP were released, respectively; although, in both systems the smallest molecular weight amino acids, glycine and alanine, were preferentially released. The free amino acids content obtained by enzymatic hydrolysis with commercial proteases Alcalase and Novozym was much lower with the highest hydrolysis yield determined for histidine. These results have been supported by size exclusion chromatography analysis.