With the improvement of living standards, people's concept of consumption of food is no longer confined to safety and health. Instead, it puts forward higher requirements on various aspects such as color, smell, taste and nutrition of food.
EHV technology can not only sterilize food, but also keep the original functional ingredients and nutrients of the food to a limited extent. At the same time, it also overcomes the shortcomings of processing technologies such as irradiation, microwave and electromagnetic field, and can save resources and reduce pollution .
Although the application of EHV technology in food processing in China is still in its infancy, some domestic enterprises such as fresh oysters, fresh sea cucumber and fresh fruit juice have been successfully processed by the domestic EHV equipment and technologies and are listed on the market. This means that our country has made breakthroughs in the manufacture of EHV technology and equipment, which is of great significance in promoting the development of EHV technology in the food industry in our country.
1, EHV technology concept
Ultra-high pressure technology, also known as ultra-high pressure sterilization technology, refers to the use of more than 100MPa pressure, at room temperature or lower temperature conditions, the food enzymes, proteins and starch and other biological macromolecules change activity, degeneration or gelatinization Dead bacteria and other microorganisms in a food processing method.
EHV technology in food sterilization, processing technology has unique advantages:
1) the role of uniform, instantaneous and efficient;
2) easy to control, safe operation, low energy consumption, less pollution;
3) can maintain the inherent nutritional quality of food and flavor;
4) improve the structure of biopolymer, adjust the quality of food;
5) different pressure effects of different nature.
2, EHV technology processing principle
The principle of ultrahigh-pressure processed food is that the distance between small molecules (such as water molecules) in the food will be reduced when the food is in the state of ultra-high pressure, while the material composed of macromolecules such as protein in the food remains the same. At this moment, the water molecules will infiltrate and fill, and enter and adhere around the amino acids inside the macromolecules such as proteins, thereby changing the nature of the protein. When the pressure is reduced to atmospheric pressure, the "denatured" Is elongated, so that part of the three-dimensional structure was destroyed, so that the protein coagulation, starch denaturation, enzyme inactivation or activation, killing of bacteria and other microorganisms, the organization of food to improve the organization, contributed to the formation of new food.
Only acting on non-covalent bonds is a unique property of EHV technology. Therefore, it has no obvious effect on the covalent bonding of low molecular weight substances such as vi***ins, pigments and flavors, so it can better maintain the original nutritive value of food, Color and natural flavor.
3, the application of high pressure in food processing
EHV processing technology can not only be used for food sterilization, enzyme and texture improvement, but also the nutritional value of food, color and natural flavor also has a unique protective effect.
At present, EHV technology has been widely used in the extraction of meat products, dairy products, egg foods, fruit and vegetable products, aquatic products processing and active ingredients.
1) Application of ultra-high pressure in the processing of fruits and vegetables
Sterilization of fruit and vegetable products is the most successful application of EHV technology in food processing. Compared with traditional heat sterilization, EHV technology can achieve the effect of sterilizing, inhibiting the enzyme and improving the properties of food at normal temperature or lower temperature without destroying the freshness and nutrients of fruits and vegetables, which is in line with consumers' And the flavor of the request.
Fresh juice is rich in protein, vi***ins, amino acids and reducing sugars and other nutrients, the traditional heat sterilization will make these nutrients loss, EHT sterilization technology can effectively avoid the loss of a large number of nutrients in the juice.
Sterilization using high-pressure technology not only kills microorganisms in the fruit, but also reduces enzyme activity.
Sensory quality of the juice includes color, aroma, taste and so on. Ultrahigh-pressure sterilization belongs to the technology of cold sterilization. Its operation process is carried out at normal temperature. Ultra-high pressure only acts on non-covalent bond, which does not affect the covalent bond. Therefore, the original taste, flavor and color of the juice can be well maintained.
2) EHV in the meat processing applications
Using ultra-high pressure technology to treat meat products can effectively improve the tenderness, flavor, color, maturity and other characteristics of meat products, and can also extend the shelf life of meat products. Meat tenderness reflects the texture and quality of meat, refers to the taste of meat when eating tender old, it is consumers commonly used to evaluate the merits of meat quality indicators.
3) UHP application in aquatic products processing
Aquatic products processing requirements with the original flavor of aquatic products, color, taste and texture. Commonly used dry treatment, heat treatment can not meet the requirements. The ultra-high pressure treated aquatic products can better maintain the original fresh flavor.
4) Ultra-high pressure in alcohol processing applications
The natural aging of wine in wine production is a time-consuming, energy-intensive process. EHV technology can play an important role in the promotion of wine. In addition, EHV technology also has a good bactericidal effect in beer.
5) EHV in the processing of egg products
When pressure of 600 MPa acts on the egg, the egg is frozen and solidified. Compared with the cooked egg, the egg after the ultra-high pressure treatment is very tasty, the yolk is bright yellow and has good elasticity. Studies have shown that ultra-high pressure treated protein denatured gels are softer and more elastic than gelatin gel and have a higher digestibility. In addition, amino acids and vi***ins are not lost, preserving the natural flavor of eggs and not generating other substances.
6) Ultra-high pressure in the dairy processing applications
Heat treatment is the most common processing method in modern dairy production. Although it can kill some or all of the dairy micro-organisms, destroy enzymes, extend the shelf life of the product. But at the same time it can also bring adverse effects to the product. EHV technology can not only ensure the microbial safety of the dairy product, but also maintain the inherent nutritional quality, flavor and color of the dairy product.
Casein is the major protein in milk. Ultra-high pressure treatment reduces the diameter of the casein micelles and increases the hydrophobic groups exposed on the surface of the milk proteins, causing the denatured whey protein to clot.
7) EHV technology in the extraction of active ingredients
Compared with the traditional extraction methods, EHV technology has the advantages of short extraction time, high extraction yield and low energy consumption in the extraction of active ingredients. Ultrahigh-pressure extraction can be carried out at room temperature, to avoid the thermal effect caused by changes in the active ingredient structure, loss and reduction of physiological activity.
At present, EHV technology has been applied in the extraction of polysaccharides, flavonoids, saponins, alkaloids, terpenes and volatile oils, phenols and readily oxidizable components, and organic acids.
EHV technology is one of the cutting-edge technologies in the 21st century. It is called the hot spot of science and technology and is a revolution in the food industry. Ultra-high pressure food retains the original color, smell, taste and nutrition, this advantage is just to cater to the modern human advocate of nature, the pursuit of natural, low-processed foods consumer psychology, in line with the current requirements of green food.
However, there are also some shortcomings in EHV technology. For example, the investment cost of EHV equipment is high, the requirements for equipment sealing and strength are high, and the service life of equipment and supplies is short. The basic theoretical system of EHV technology needs to be perfected. The conditions of EHV sterilization are demanding. The main limiting factors need to be further studied.
In addition, the relationship between the changes of food components after the ultra-high pressure treatment and the interaction of the components is not yet clear. China is still in its infancy in the field of high-voltage technology. Compared with the world's advanced level, there is still a large gap between China and the rest of the world. Therefore, our country should speed up the research and application of EHV technology.