Photo-Thermally Sequentially Responsive Shape Memory Polymers Based on Side-Chain Azobenzene-Functionalized Epoxy.

High-pressure carbon dioxide (HPCD) is a non-thermal pasteurization technique that utilizes elevated levels of carbon dioxide under pressure to inactivate microorganisms in food products. This method has gained attention due to its effectiveness in extending the shelf life of various foods while preserving their sensory and nutritional qualities. HPCD has demonstrated effectiveness against various bacteria, yeast, and molds, making it suitable for a range of food products. Since it is a non-thermal process, the food maintains its freshness, flavor, and nutritional content better than heat treatments. By inactivating spoilage microorganisms, HPCD can significantly extend the shelf life of products like dairy, juices, sauces, and ready-to-eat meals. The antimicrobial effects of HPCD can reduce or eliminate the need for chemical preservatives. Fruit juices and carbonated drinks can benefit from HPCD, as they help eliminate pathogens while maintaining taste and freshness. Milk and cheese can undergo HPCD to improve safety and shelf life without compromising quality. Pre-packaged meals can be treated with HPCD to ensure safety and extend shelf life. In the context of sparkling drinks, HPCD involves dissolving carbon dioxide (CO) into the beverage at high pressures, which not only carbonates the drink but also enhances its antimicrobial properties. The CO under high pressure exhibits antimicrobial effects, which can help in inactivating spoilage microorganisms and pathogens. The carbonic acid formed when CO dissolves in the beverage lowers the pH, creating an environment that is less favorable for microbial growth. HPCD can be used for fruit juices that are carbonated, targeting both microbial safety and flavor. High-pressure carbon dioxide treatment helps in maintaining the quality and safety of sparkling waters by minimizing microbial contamination. HPCD can also be adapted for soft drinks to improve safety and extend shelf life while ensuring optimal carbonation. By dissolving CO under high pressure, HPCD ensures a uniform distribution of bubbles throughout the liquid, leading to a consistent drinking experience. The antimicrobial properties of dissolved carbon dioxide help in inactivating spoilage microorganisms and pathogens in sparkling drinks. This is especially important for beverages that are minimally processed or have a shorter shelf life without preservatives. High-pressure CO can inhibit unwanted fermentation processes (e.g., by yeast) that may occur in sugar-containing drinks, helping to maintain the desired flavor profile and carbonation level. The pressure involved in the HPCD process can lead to considerations in packaging design. Containers must be capable of withstanding the high pressures involved, leading to innovations in packaging materials. Ongoing research and development may expand its applications and address any technical challenges associated with implementation. Dohrn et al. measured the phase equilibrium data in the glucose-water-CO and glucose-water-ethanol-CO systems at temperatures up to 343 K and pressures up to 30 MPa. Their results show that CO solubility tends to decrease by increasing the glucose while adding ethanol resulting in increases in the solubility of glucose in the vapor phase. The results show that the solubility of glucose in pure supercritical CO is small. Calix et al. measured the CO solubility in pure water, ascorbic acid-sugars-water, citric acid-sugars-water, commercial orange juice, and apple juice. Their results showed that CO solubility in real juices was lower than in pure water. Sugars generally decrease CO solubility in water. This is because sugar molecules compete with CO molecules for interactions with water molecules. The higher the sugar concentration, the lower the CO solubility. This is a colligative property effect. High sugar content also increases the viscosity of the juice. Higher viscosity can slow down the rate at which CO dissolves or escapes, but it doesn’t necessarily change the equilibrium solubility as much as the competitive effect. In pure water, the addition of some acids can slightly increase CO solubility through a phenomenon called “salting-in.” This involves the ions from the acid interacting with water molecules, which may indirectly enhance CO interaction with water. However, this effect is usually small at the concentrations typically found in juices. In summary, while the acidic nature of juices might slightly enhance CO solubility, the high sugar content generally decreases it. The precise effect depends on the specific composition of the juice. The amount of CO in the food plays an important role in to scale-up of laboratory experiments for commercial application of HPCD. Experimental measurements can be time-consuming, labor-intensive, and require specialized equipment (e.g., high-pressure cells, and analytical instruments). Each measurement only provides data for a single set of conditions. It’s often impractical to exp