Fresh-keeping packaging
American researchers have placed a layer of plastic film containing a chemical substance called Ammosorb in food packaging bags, which can remove oxygen from the packaging and keep the packaged food from spoiling for a long time. This chemical substance remained in a dormant state until it was exposed to special light waves. Chemical reactions only begin to manifest after being exposed to special light waves. This means that when packaging food, there is no need for complex deaeration treatment. It is only necessary to expose it to special light waves in the last process of food packaging.
Russian experts have added dehydrated acidifiers, various mineral salts and enzymes and other substances to the polymers of packaging materials. The surface of packaging bags rich in these substances can absorb the excess moisture in the packaged food, kill bacteria, and thereby improve the internal environment of the packaging bags. Meanwhile, the enzymes in the additives can also regulate the smell of food and create a survival space for the nutrients in the food.
A Japanese chemical industry company has successfully developed an antibacterial plastic packaging material. This antibacterial plastic packaging product is made by mixing synthetic materials such as fibrous plastic and polypropylene with an antibacterial agent used in food films. It can prevent the reproduction of microorganisms and bacteria, prevent the deterioration of the food, cosmetics or drugs it contains, and greatly extend the shelf life.
Modified atmosphere packaging
In recent years, a type of modified atmosphere packaging bag for fruit and vegetable food packaging has emerged in the European market. This kind of high-oxygen spontaneous modified atmosphere packaging bag can adjust the combination ratio of oxygen, carbon dioxide and nitrogen inside the bag according to the physiological characteristics of different fruit and vegetable foods. For example, for perishable fruit and vegetable foods, 80-90% oxygen and 10-20% carbon dioxide can be used. This kind of packaging can inhibit enzyme activity and prevent Browning of fruit and vegetable foods. Prevent fermentation caused by anaerobic respiration and maintain the quality of fruit and vegetable foods; It has the advantages of effectively inhibiting the growth of aerobic and anaerobic microorganisms and preventing rot, etc. Fresh mushrooms packaged in high-oxygen modified packaging bags can have a shelf life of up to 8 days at a temperature of 8℃.
Microwave packaging
The Swedish Sprinter company has produced a flat disc-type microwave packaging. This packaging is made of C-PET material, with PET lining, multi-layer composite and reinforcing ribs pressed out. Food packaged in this way can be directly put into the microwave oven for baking after being taken out of the refrigerator and can withstand a high temperature of 230℃.
Due to the disadvantages of packaging made of composite materials of aluminum foil and certain plastics, such as being opaque, not easy to recycle, and not suitable for microwave processing, the SiOx-coated material developed in recent years can be used as a substitute. SiOX is a layer of silicon oxide coated on substrates such as PET, PA, and PP. This coating features high barrier properties, high microwave permeability, and transparency. It can be used for soft packaging of food during high-temperature cooking and microwave processing, and can also be made into packaging containers for beverages and edible oil.
Heat-resistant packaging
Two companies in Japan have jointly developed a packaging bag that can be used for cooking rice. This bag has two layers. The outer layer is made of highly heat-resistant nylon, and the inner layer is polyethylene film. There is also a water level line printed inside the bag indicating the amount of water to be released per meter. When using it, just put the rice into the bag, add water to the corresponding water level line, then put the bag into the pot and cook for 20 minutes. The rice will be cooked. This kind of packaging is very suitable for use in the wild.
Frozen packaging
A company in San Francisco, the United States, has designed and produced a vacuum-packed food preservation bag, which can effectively prevent food from freezing and deteriorating in the refrigerator. This packaging bag is composed of three layers, one of which is nylon, used to enhance its strength. An air extraction channel is also implanted on the bag wall. This kind of vacuum packaging bag is resistant to freezing, can be heated in a microwave, boiled, washed and resealed. The experimental results show that the food vacuum-packed in this packaging bag has no weight loss, no ice chips on the bag wall, and no obvious discoloration or other deterioration phenomena. The vacuum packaging bag can extend the freezing preservation time of food without deterioration by 3 to 5 times compared with ordinary preservation bags.
France has successfully developed a kind of insulated bag for frozen food suitable for supermarkets. Thus, the problem of the change in flavor of food taken out of the supermarket freezer, thawed and then refrozen has been solved. It is reported that the appearance of this kind of insulated packaging bag is similar to that of plastic and paper bags for supermarket goods. The bag is divided into two layers. The outer layer is made of ordinary plastic or thick paper, and the inner layer is an insulating layer made of nylon fibers. The top of the bag is tightly sealed. This bag has an insulating effect. There are various insulating bags that can keep warm at different temperatures such as 3, 2, 0, -4, and -10 degrees Celsius, as well as insulating bags for long-term use, and their capacities vary.
Convenient packaging
A self-heating packaging has emerged in the UK market. It is a multi-layered, seamless container made by injection molding, with the inner layers divided into multiple compartments, allowing the product to self-heat. Its heating principle is as follows: When the user removes the foil from the container and presses the bottom of the container, the water and limestone inside the container will undergo a chemical reaction, releasing heat energy and thereby heating the product.
The packaging industry in the United States has developed a kind of packaging that can be "Instant Cool". This packaging has a condenser, an evaporation grid and a bag of desiccant made of salt inside. The vapor and liquid produced by catalytic action during cooling will be stored at the bottom of the packaging. It can lower the temperature of the items in the container within a few minutes.
