Effect of high pressure carbon dioxide on the browning inhibition of sugar-preserved orange peel

Bioavailability and mechanisms of dietary polyphenols affected by non-thermal processing technology in fruits and vegetables

Plant polyphenols play an essential role in human health. The bioactivity of polyphenols depends not only on their content but also on their bioavailability in food. The processing techniques, especially non-thermal processing, improve the retention and bioavailability of polyphenolic substances. However, there are limited studies summarizing the relationship between non-thermal processing, the bioavailability of polyphenols, and potential mechanisms. This review aims to summarize the effects of non-thermal processing techniques on the content and bioavailability of polyphenols in fruits and vegetables. Importantly, the disruption of cell walls and membranes, the inhibition of enzyme activities, free radical reactions, plant stress responses, and interactions of polyphenols with the food matrix caused by non-thermal processing are described. This study aims to enhance understanding of the significance of non-thermal processing technology in preserving the nutritional properties of dietary polyphenols in plant-based foods. It also offers theoretical support for the contribution of non-thermal processing technology in improving food nutrition.

The regulation of carbon dioxide on food microorganisms: A review

This review presents a survey of two extremely important technologies about CO2 with the effectiveness of controlling microorganisms - atmospheric pressure CO2-based modified atmosphere packaging (MAP) and high pressure CO2 non-thermal pasteurization (HPCD). CO2-based MAP is effectively in delaying the lag and logarithmic phases of microorganisms by replacing the surrounding air, while HPCD achieved sterilization by subjecting food to either subcritical or supercritical CO2 for some time in a continuous, batch or semi-batch way. In addition to the advantages of healthy, eco-friendly, quality-preserving, effective characteristic, some challenges such as the high drip loss and packaging collapse associated with higher concentration of CO2, the fuzzy mechanisms of oxidative stress, the unproven specific metabolic pathways and biomarkers, etc., in CO2-based MAP, and the unavoidable extraction of bioactive compounds, the challenging application in solid foods with higher efficiency, the difficult balance between optimal sterilization and optimal food quality, etc., in HPCD still need more efforts to overcome. The action mechanism of CO2 on microorganisms, researches in recent years, problems and future perspectives are summarized. When dissolved in solution medium or cellular fluids, CO2 can form carbonic acid (H2CO3), and H2CO3 can further dissociate into bicarbonate ions (HCO3-), carbonate (CO32-) and hydrogen cations (H+) ionic species following series equilibria. The action mode of CO2 on microorganisms may be relevant to changes in intracellular pH, alteration of proteins, enzyme structure and function, alteration of cell membrane function and fluidity, and so on. Nevertheless, the effects of CO2 on microbial biofilms, energy metabolism, protein and gene expression also need to be explored more extensively and deeply to further understand the action mechanism of CO2 on microorganisms.

The effect of supercritical carbon dioxide on the physiochemistry, endogenous enzymes, and nutritional composition of fruit and vegetables and its prospects for industrial application: a overview

Consumers have an increasing demand for fruit and vegetables with high nutritional value worldwide. However, most fruit and vegetables are vulnerable to quality loss and spoilage during processing, transportation, and storage. Among the recently introduced emerging technologies, supercritical carbon dioxide (SCCO2) has been extensively utilized to treat and maintain fruit and vegetables mainly due to its nontoxicity, safety, and environmentally friendly. SCCO2 technology generates low processing costs and mild processing conditions (temperature and pressure) that allow for the application of CO2 at a supercritical state. This review aimed to summarize the current knowledge on the influence of SCCO2 technology on the quality attributes of fruit and vegetable products, such as physicochemical properties (pH, color, cloud, particle size distribution, texture), sensory quality, and nutritional composition (ascorbic acid, phenolic compounds, anthocyanins, carotenoids, and betalains). In addition, the effects and mechanisms of the SCCO2 technique on endogenous enzyme inactivation (polyphenol oxidase, peroxidase, and pectin methylesterase) were also elucidated. Finally, the prospects of the SCCO2 technique for industrial application was discussed from the economic and regulatory aspect.

Effect of CO2 on the spoilage potential of Shewanella putrefaciens target to flavour compounds

To investigate the regulation mechanism of CO₂ (0% CO₂, 20% CO₂, 60% CO₂, and 100% CO₂) on the spoilage potential of S. putrefaciens target to flavour compounds, the metabolic activity of S. putrefaciens and the changes in flavour compounds extracted from inoculated large yellow croakers were evaluated. Results showed that CO₂ significantly reduced biofilm formation capacity and suppressed synthesis of intracellular adenosine triphosphate (ATP). The production of unpleasant flavour compounds, such as total volatile basic nitrogen (TVB-N), trimethylamine (TMA), inosine (HxR), hypoxanthine (Hx), histidine, lysine, histamine, putrescine, 1-octen-3-ol, hexanal and benzaldehyde, was inhibited by CO₂. The hydrolysis and oxidation of lipid in CO₂-treated samples were alleviated and unsaturated fatty acids (UFAs) were in a higher percentage. In summary, CO₂ efficiently reduced the spoilage potential of S. putrefaciens and contributed to better flavour quality of samples during 4 °C storage. A more effective inhibition by 100% CO₂ was observed.

Evaluation Study on Extraction of Anthocyanins from Red Cabbage Using High Pressure CO2 + H2O: A Fuzzy Logic Model and Metabolomic Analysis

In this work, a fuzzy logic model was developed to elucidate the extraction performance of high-pressure CO2 + H2O compared with traditional H2O extraction and aqueous ethanol extraction. The high-pressure CO2 + H2O group acquired the highest comprehensive score considering yield, quality and stability. Both targeted and untargeted metabolomics results proved that the polarity of water was slightly modified; in particular, with the evidence from the untargeted metabolomics data, a higher proportion of water-insoluble compounds (2-methylindole, 3-formylindole, guanine, tyrosine and tryptophan) obtained by high-pressure CO2 + H2O extraction compared with traditional H2O extraction has been reported for the first time. Finally, the “3I” extraction mechanism of high-pressure CO2 + H2O is proposed, which offers an improvement in the solid–liquid mass transfer efficiency of phytochemicals, improving the polarity of solution and the isolation of O2.