The difference between vacuum packaging and modified atmosphere packaging

1. Vacuum packaging is also called decompression packaging. It is to completely remove the air in the packaging container and keep the bag under high decompression condition. The air is rare, which is equivalent to the low oxygen effect, so that the microorganisms have no living conditions to achieve fresh and no fruit. The purpose of the disease rot. At present, there are vacuum packaging, aluminum foil packaging, glassware, plastic and composite packaging in plastic bags. Packaging materials can be selected according to the type of item. Since the fruit is a fresh food, it is still undergoing respiration, and high oxygen deficiency can cause physiological diseases. Therefore, the fruit is less vacuum-packed.

The mechanism of vacuum packaging: its purpose is to reduce the oxygen content in the package, prevent the deterioration of the packaged food, maintain the color and aroma of the food, and extend the shelf life.

The main function of vacuum packaging is to remove oxygen, which is beneficial to prevent food spoilage. The principle is also relatively simple, because the deterioration of food mold is mainly caused by the activity of microorganisms, and the survival of most microorganisms (such as mold and yeast) requires oxygen. Vacuum packaging is the use of this principle to remove oxygen from the inside of the bag and food cells, so that the micro-objects lose the "living environment." The experiment proves that when the oxygen concentration in the package 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 breeding. (Note: Vacuum packaging can not inhibit the deterioration and discoloration of food caused by anaerobic bacteria reproduction and enzyme reaction, so it needs to be combined with other auxiliary methods, such as refrigeration, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt Pickled, etc.)

2. Atmospheric preservation, as the name suggests, is to control the proportion of gas to achieve the purpose of storage and preservation. The modified atmosphere preservation technology is a technology for prolonging the storage life and shelf life of food by adjusting the ambient gas. The basic principle is: in a certain closed system, the adjustment gas different from the normal atmospheric components is obtained through various adjustment methods, and the inhibition is caused. The physiological and biochemical processes of food loss and the activities of microorganisms.

The key to air conditioning technology is to regulate the gas. In addition, while choosing to adjust the gas composition and concentration, two important control conditions of temperature and relative humidity must also be considered. It is important not only to pay attention to their individual influence, but also to pay attention to the overall impact of the overall environment composed of various conditions.

There are two main methods currently widely used in China:

1. CA air conditioning storage and preservation (gas-conditioning fresh-keeping cold storage) Domestic high-tech enterprises research, using mechanical equipment, artificially control the gas in the atmosphere of the cold storage storage, to achieve fruit preservation. The modified atmosphere cold storage requires precise control of the concentration of gas components required for different fruits and strict control of temperature and humidity. The temperature can be the same as the storage temperature of the refrigerator or slightly higher than the temperature of the refrigerator to prevent low temperature damage. The combination of air conditioning and low temperature, the preservation effect (color, hardness, etc.) is better than ordinary refrigeration, and the preservation period is significantly prolonged.

2. MA air conditioning storage and preservation (plastic film bag modified atmosphere preservation, also known as modified atmosphere packaging) According to the physiological characteristics of food and preservation needs, the food is stored in a suitable proportion of packaging to extend its shelf life. It is widely used in fresh fruits and vegetables to keep fresh, and grows at a rate of 20% per year. The combination of fresh-keeping packaging and cold storage is almost the same as the air-conditioning fresh-keeping cold storage. There are two types of MA air conditioning packages: one is passive air-conditioning packaging, that is, fruit wrapped with plastic film, which uses breathing to reduce oxygen content and adjusts the ratio of oxygen to carbon dioxide through packaging exchange gas; the other is active atmosphere control. That is to say, according to the breathing speed of different fruits, the mixed gas is filled, and the film with different air permeability is used, but due to the complicated technology and high requirements on the variety and performance of the packaging materials, it has not been widely used in China.