The temperature changes by depending on the target pressure and the chemical composition of the food.
Example:
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The water temperature increase to 3°C per 100 MPa but it can be significant higher for compressible food ingredients such as fats. Therefore, the temperature increase is higher for foods with higher fat content.
The HPP processing undamaged the vitamins and minerals content from the food such as vitamins, flavour compounds, pigment and other.
Example:
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Pressure treatment of non-pasteurized citrus juices provides a fresh-like flavor with no loss of vitamin C and a shelf life of approximately 17 months. (Rahman, 2007)
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Jams obtained by high-pressure processing retain the taste and color of fresh fruit, unlike conventional jams produced by heat. (Rahman, 2007)
The gelatinization of carbohydrates being achieved and proteins can be denaturing through pressure treatment.
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Example:
​The egg preserved in two type of processes, which the thermal-processed and the high pressure processed. From the figure, it shows the hardboiled egg from the HPP changes in appearance and color.
According to Huang (2014) and Maria (2013) as cited in (Rezvan Ghalavand, Nooshin Nikmaram and Mohammad Hassan Kamani, 2015), pressure at 50 MPa can inhibit protein synthesis in microorganisms and reduce the number of ribosomes. Pressure of 100 MPa can lead to denaturation of proteins and 200 MPa pressure causes damage to the internal structure and cell membrane. Meanwhile, at pressure 300 MPa or more causes rupture of cell membranes and withdrawal of intracellular contents which will lead to bacteria death. In HPP operations at room temperature and 400-600 MPa will reduce numbers of vegetative bacteria by 4 log units and inactivate certain enzymes with changes in the organoleptic properties of the food. (High Pressure Processing of Foods, 2015)
Nevertheless, the resistance of bacteria and other microorganisms to HPP is highly inconstant. For example, as Listeria monocytogenes which is a gram positive bacteria can exhibit higher resistance than Salmonella which is a gram negative bacteria. Moreover, spores of both bacteria and moulds are mostly resistant to inactivation by HPP. However, viruses depend on their structural diversity for pressure resistance. (High Pressure Processing of Foods, 2015)