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Can food be sterilized by vacuum packaging?

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the market demand for packaged cooked food is very large, but consumers are increasingly affected by the continuous emergence of food problems, and their requirements for the quality of products are constantly improved (including color, aroma and taste), and the nutritional components of products need to be retained to the greatest extent without excessive use of preservatives. Vacuum packaged cooked food sterilization equipment adopts microwave sterilization. It is a typical vacuum packaging food sterilization equipment. Because the temperature of cooked food can be increased accordingly, it has faster sterilization speed and better sterilization effect. It can realize the sterilization and preservation of agricultural and sideline products and prolong the shelf life of agricultural and sideline products, which is of great help to the sales of products. Microwave sterilization and preservation of fresh mushrooms and bamboo shoots have been successfully realized, and good results have been achieved

considering the needs of consumer safety and consumer psychology, modern food processing technology and technology require to retain the color, aroma, taste and nutritional components of food to the greatest extent. However, the traditional food thermal sterilization method is far from meeting this requirement. In recent years, some new cold sterilization technologies have been developed at home and abroad, such as ultra-high pressure sterilization, ultra-high voltage pulsed electric field sterilization, pulsed strong light sterilization, radiation sterilization, UV sterilization and other cold sterilization technologies, which have attracted great attention of food science researchers

cold sterilization refers to a safe and efficient sterilization method in which the food temperature does not rise or rises very low in the sterilization process. Cold sterilization is not only conducive to maintaining the physiological activity of food functional components, but also conducive to maintaining color, aroma, taste and nutritional components

ultra high pressure sterilization

ultra high pressure sterilization is to pack food materials in some way, put them into liquid medium and act under the pressure of 100 ~ 1000 MPa for a period of time to make them meet the sterilization requirements. Its basic principle is the lethal effect of pressure on microorganisms, which is mainly realized by destroying its cell wall, coagulating proteins, inhibiting the activity of enzymes and the replication of genetic substances such as DNA [1]. Generally speaking, the higher the pressure, the better the sterilization effect. However, prolonging the compression time under the same pressure does not necessarily improve the sterilization effect. Under the pressure of 400 ~ 600 MPa, it can kill bacteria, yeast and mold, avoiding the adverse changes caused by general high-temperature sterilization. The progressiveness of ultra-high pressure cold sterilization technology is high-pressure and normal temperature sterilization. After the food is treated with this technology, it not only has high bactericidal efficiency, but also can retain the nutrients in the food. The food has good taste, natural color, high safety and long shelf life, This is an advantage that the traditional high-temperature thermal sterilization method does not have. At present, ultra-high pressure sterilization has been applied in the production of fruits and vegetables, yogurt, jam, dairy products, aquatic products, egg products and high viscosity food abroad [2]

sterilization by ultra-high voltage pulsed electric field

sterilization by pulsed electric field generated by high voltage pulse. The alternating action of electric field and magnetic field generated by pulse increases the permeability of cell membrane and weakens the strength of membrane. Finally, the membrane is broken, the substances inside the membrane flow out, the substances outside the membrane go deep, and the cell body dies. Electromagnetic field produces ionization, blocks the normal biochemical reaction and metabolism of cell membrane, and changes the substances in bacteria. This technology avoids a series of phenomena such as protein denaturation and vitamin damage caused by heating

1. Definition of vacuum packaging vacuum packaging puts food into the packaging bag, extracts the air in the packaging bag, and completes the sealing process after reaching the predetermined vacuum degree. Vacuum inflatable packaging put the food into the packaging bag, extract the air in the packaging bag to reach the predetermined vacuum, then fill it with nitrogen or other mixed gases, and then complete the sealing process

2. Action mechanism the main function of vacuum packaging is to remove oxygen to help prevent food deterioration. Its principle is also relatively simple. Because the moldy deterioration of food is mainly caused by the activities of microorganisms, and the survival of most microorganisms (such as molds and yeasts) requires oxygen. Vacuum packaging uses this principle to pump out the oxygen in the packaging bag and food cells, so that micro objects lose their living environment. Experiments show that when the oxygen concentration in the packaging bag is ≤ 1%, the growth and reproduction speed of microorganisms will drop sharply. When the oxygen concentration is ≤ 0.5%, most microorganisms will be inhibited and stop reproduction. (Note: vacuum packaging can not inhibit the deterioration and discoloration of food caused by anaerobic bacteria and enzyme reaction, so it needs to be combined with other auxiliary methods, such as cold storage, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt pickling, etc.) In addition to inhibiting the growth and reproduction of microorganisms, another important function of vacuum deoxidation is to prevent food oxidation. Because fat foods contain a large number of unsaturated fatty acids, they are oxidized by oxygen, which makes the food taste and deteriorate. In addition, oxidation also causes the loss of vitamin A and C, and the unstable substances in food pigments are darkened by oxygen. Therefore, deoxidization can effectively prevent food deterioration and maintain its color, aroma, taste and nutritional value. In addition to the oxygen removal and quality assurance functions of vacuum packaging, the main functions of vacuum inflatable packaging are compression resistance, gas blocking and preservation, which can more effectively maintain the original color, aroma, taste, shape and nutritional value of food for a long time. In addition, many foods are not suitable for vacuum packaging, but must use vacuum inflatable packaging. Such as crisp and fragile food, easily caked food, easily deformed and oily food, food with sharp edges and corners or high hardness that will pierce the packaging bag, etc. After the food is vacuum inflated and packaged, the inflation pressure in the packaging bag is greater than the atmospheric pressure outside the packaging bag, which can effectively prevent the food from being crushed and deformed under pressure and does not affect the appearance of the packaging bag and the printing and decoration. Vacuum packaging put the food into the packaging bag, extract the air in the packaging bag, and complete the sealing process after reaching the predetermined vacuum degree. Vacuum inflatable packaging put the food into the packaging bag, extract the air in the packaging bag to reach the predetermined vacuum, then fill it with nitrogen or other mixed gases, and then complete the sealing process

action mechanism the main function of vacuum packaging is to remove oxygen to help prevent food deterioration. Its principle is also relatively simple. Because food mildew and deterioration are mainly caused by the activities of microorganisms, and the survival of most microorganisms (such as molds and yeasts) requires oxygen. True empty packaging uses this principle to
pump out the oxygen in the packaging bag and food cells, so that micro objects lose their living environment. Experiments show that when the oxygen concentration in the packaging bag is ≤ 1%, the growth and reproduction speed of microorganisms will drop sharply. When the oxygen concentration is ≤ 0.5%, most microorganisms will be inhibited and stop reproduction. (Note: vacuum packaging can not inhibit the deterioration and discoloration of food caused by anaerobic bacteria and enzyme reaction, so it needs to be combined with other auxiliary methods, such as cold storage, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt pickling, etc.) In addition to inhibiting the growth and reproduction of microorganisms, another important function of vacuum deoxidation is to prevent food oxidation. Because fat foods contain a large number of unsaturated fatty acids, they are oxidized by oxygen, which makes the food taste and deteriorate. In addition, oxidation also causes the loss of vitamin A and C, and the unstable substances in food pigments are darkened by oxygen. Therefore, deoxidization can effectively prevent food deterioration and maintain its color, aroma, taste and nutritional value. In addition to the oxygen removal and quality assurance functions of vacuum packaging, the main functions of vacuum inflatable packaging are compression resistance, gas blocking and preservation, which can more effectively maintain the original color, aroma, taste, shape and nutritional value of food for a long time. In addition, many foods are not suitable for vacuum packaging, but must use vacuum inflatable packaging. Such as crisp and fragile food, easily caked food, easily deformed and oily food, food with sharp edges and corners or high hardness that will pierce the packaging bag, etc

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