Pascalization - non-thermal methods of food preservation

Increasingly health-conscious consumers demand better food quality. Consumers are interested in food that possesses features sensory attributes resembling freshness, food without chemical additives, and safe food. Food with a "clean label" is gaining increasing attention among consumers, emphasizing that the food is natural, fresh, and free from chemical additives. The heightened interest in high-quality food from consumers has led to the development of non-thermal food processing technologies, providing an alternative to conventional heat treatment. 

Non-thermal food processing methods allow the preservation of the sensory properties and nutritional values of food, which is not possible with traditional thermal pasteurization. An example of a non-thermal food preservation method is the high-pressure processing (HPP) – paskalizacja (HPP - high pressure processing). The U.S. Food and Drug Administration has officially approved HPP as a non-thermal pasteurization technology that can replace traditional pasteurization in the food industry. In the market, one can find high-pressure processed juices, fruits, vegetables, meat, seafood, ready-to-eat meals, and sauces.

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HPP method operating principle

Food products that have been hermetically sealed are placed in a thermally isolated, airtight container, and poddawane działaniu bardzo wysokiego ciśnienia The pressure (100–600 MPa) transmitted through a liquid medium (usually water) ensures the pasteurization effect by uniformly and instantly applying high pressure. According to the principle of adiabatic heating, a 100 MPa pressure increase results in a water temperature rise of approximately 3°C. The initial pasteurization temperature is controlled within the range of 5–10°C, meaning that after increasing the pressure to 600 MPa, the water temperature will not exceed 30°C. Thus, HPP reduces the impact of temperature on food ingredients. 

The two fundamental principles, namely the isostatic principle and Pascal's principle, govern the uniform application of pressure to food products in a closed vessel. According to the isostatic principle, when pressure is applied to a liquid medium in a closed environment, equal pressure is exerted on objects at any point in the surroundings, regardless of the shape and size of the object. Pascal's principle states that the change in pressure caused by applying an external force to a fluid at rest in a closed container is transmitted uniformly and without loss to every portion of the fluid and the walls of the container. Therefore, the shape and size of food packaging have no effect on the effects of high-pressure pasteurization. In the same batch, food products of different volumes can be processed. 

Advantages and disadvantages of the HPP method

HPP surpasses traditional heat processing technologies in the following respects. It can be performed at room temperature, which eliminates the consumption of energy required for heating and subsequent cooling. Food products during HPP are in their final packaging and do not have direct contact with processing equipment, which prevents the formation of secondary contaminants after pasteurization and allows for the recovery and reuse of the pressure-transmitting agent.As HPP has advantages such as low energy consumption and low pollution levels, it is a relatively environmentally friendly processing technology. Additionally, this technology ensures microbiological safety of food. without the addition of preservatives and allows processed food to retain its natural flavors and nutritional values Therefore, HPP technology is considered a minimal processing technology that ensures both food safety and preserves the taste and nutritional properties of the original food raw material. 

The HPP method allows for the preservation of functional ingredients and reduces the inactivation of antioxidants (carotenoids, polyphenols, vitamin C, anthocyanins). However, due to the high investment costs in HPP equipment, the production costs of HPP products are slightly higher than those of non-HPP products, resulting in resulting in a higher average unit price for HPP products. Therefore, the use of HPP for preservation in the food industry is much less common than traditional thermal pasteurization. Due to the differences in production costs, distinct market positioning strategies should be adopted for HPP products and thermally pasteurized products. 

Pascalization in the development of the health food market

The food industry is a sector closely linked to consumer health. Consumers are willing to purchase a product only when it is completely safe. They expect food to be minimally processed, rich in nutrients, and contain functional ingredients that positively impact health. Thermal pasteurization technology is a fundamental process in the food industry, but it can have a negative impact on the appearance, taste, and nutritional value of food, failing to meet the modern society's demand for natural, fresh, and aesthetically pleasing food. The HPP (High-Pressure Processing) technology offers opportunities for developing new food products with an extended shelf life while preserving organoleptic properties and nutritional values. 

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High pressure enhances the health-promoting components of food; it is capable of meeting the needs of the majority of consumers. Therefore, the development of food products with health benefits is expected to be a trend in the development of HPP products.  The ability of HPP to maintain microbiological safety while simultaneously enhancing the nutritional value of food products will contribute to its broader application in the food or biotechnological industry.

Literature:

1. Bolumar, Tomas, et al. “High‐pressure processing of meat: Molecular impacts and industrial applications.” Comprehensive Reviews in Food Science and Food Safety 20.1 (2021): 332-368.
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3. Galanakis, Charis M. “Functionality of food components and emerging technologies.” Foods 10.1 (2021): 128.
4. Zhang, Xiaotian, Min Zhang, and Benu Adhikari. “Recent developments in frying technologies applied to fresh foods.” Trends in Food Science & Technology 98 (2020): 68-81.
5. Munekata, Paulo ES, et al. “Effect of innovative food processing technologies on the physicochemical and nutritional properties and quality of non-dairy plant-based beverages.” Foods 9.3 (2020): 288.