Effect of pressure on the inactivation of enzymes and hiochi bacteria in unpasteurized sake by low-pressure carbon dioxide microbubbles

Studying the effects of high pressure-temperature treatment on the structure and immunoreactivity of β-lactoglobulin using experimental and computational methods

The effects of high hydrostatic pressure (HHP) on the conformation and immunoreactivity of bovine β-lactoglobulin (BLG) were studied. BLG was treated under 100-600 MPa at the temperature of 20-60 °C. The immunoglobulin E (IgE) binding ability of BLG decreased when the pressure increased from 0.1 to 200 MPa. However, the IgE binding increased with the increase in pressure from 200 to 400 MPa, followed by a gradual decrease until a pressure of 600 MPa. The IgE binding ability continuously decreased with an increase in pressure at 60 °C. The conformation of HHP-treated BLG was evaluated using fluorescence spectroscopy, circular dichroism spectroscopy and molecular dynamics (MD) simulation. Increasing the temperature and pressure promoted the unfolding of BLG, causing the disappearance of some α-helixes and some β-sheets. Based on ELISA analysis, it was revealed that HHP-termperature treatment altered the immunoreactivity of BLG by altering the structures and conformational states of BLG.

High-Pressure Carbon Dioxide Used for Pasteurization in Food Industry

The demand for safe, high-quality food has greatly increased, in recent times. As traditional thermal pasteurization can significantly impact the nutritional value and the color of fresh food, an increasing number of nonthermal pasteurization technologies have attracted attention. The bactericidal effect of high-pressure carbon dioxide has been known for many years, and its effect on food-related enzymes has been studied. This novel technology has many merits, owing to its use of relatively low pressures and temperatures, which make it a potentially valuable future method for nonthermal pasteurization. For example, the inactivation of polyphenol oxidase can be achieved with relatively low temperature and pressure, and this can contribute to food quality and better preserve nutrients, such as vitamin C. However, this novel technology has yet to be developed on an industrial scale due to insufficient test data. In order to support the further development of this application, on an industrial scale, we have reviewed the existing information on high-pressure carbon dioxide pasteurization technology. We include its bactericidal effects and its influence on food quality. We also pave the way for future studies, by highlighting key areas.