Active packaging technology research

The active packaging for animals and plants has a good prospect for development. This article introduced the active packaging system, living packaging techniques and application examples of active packaging.
1. Overview of Active Packaging Active packaging refers to packaging that has a protective effect on the life of animals and plants. The characteristic of active packaging is that it can maintain the life of its packaged products, rather than simply guaranteeing its quality, flavor, and taste. Once the packaged product loses its life, it stops breathing and active packaging will lose its significance. The common active packaging includes: the packaging of animal young chicks (chicken, duck, etc.), the packaging of vegetable seedlings, the packaging of fruit (tree) seedlings, and so on. Active packaging can be simply referred to as "life-sustaining packaging" or as a keep-alive package.
The materials used to make active packaging are called active packaging materials; the related technical methods used to make active packaging are called active packaging technologies.
According to the packaging object of active packaging, active packaging can be divided into active animal packaging and active vegetable packaging. The animal active packaging focuses on the packaging of aquatic animals (such as fish). The active packaging of plants mainly studies the packaging of plant seedlings, flowers, and related fruits and vegetables.
2, active packaging system active packaging system and music active preservation system.
Active preservation system refers to a system used for active packaging to solve the life-sustaining of packaged living fresh goods over a period of time. Such a system will provide life-supporting conditions for living fresh products (animals and plants).
The active preservation system mainly includes the following aspects: (1) The oxygen control system provides oxygen or regulates the oxygen concentration in the package, and some can also absorb oxygen. The lack of oxygen in the maintenance of life, especially live fresh plants and animals, such as the seedlings of many fresh plants lost their lives due to lack of oxygen; the striking red living and fresh plants cannot provide too much oxygen. This kind of oxygen control system can also be called the oxygen supply system. The principle of oxygen control or oxygen supply is to add materials that can automatically generate oxygen in the packaging or packaging materials.
(2) Carbon dioxide control system This system is mainly used for fresh food packaging. Japan has successfully developed a low-density polyethylene film filled with magnetite, which has a high oxygen, carbon dioxide, and ethylene transmission rate. The developed carbon dioxide control system consists of a small bag containing a porous chemical substance, which is glued to the bottom of the packaging tray. When liquids in the food product leak out, the contents of the packet will release carbon dioxide, thus inhibiting the growth of microorganisms.
Some still need to absorb the carbon dioxide in the package and reduce the carbon dioxide concentration to increase the activity of the packaged product.
(3) Ethylene absorption system This system is mainly used for making plant active packaging. Since the ethylene gas released from the plant will promote the processing system and spoilage of plant fruits and vegetables, and the ethylene gas can be absorbed by porous inorganic minerals such as silica, zeolite, etc., these materials are ground into powder and mixed directly with polyethylene. Or polypropylene material, through extrusion molding, that is made with the function of absorbing ethylene film. Japan has used such films to package broccoli and other fruits and vegetables. It can also be placed on the inner wall of corrugated cardboard boxes to be used for packaging flowers and other plants. Its main drawback is that the price is too high and there is no transparency.
(4) Preservative release control system This system is actually a packaging environmental sanitation maintenance system. The system mainly inhibits microorganisms through bactericidal action.
The preservative release control system is mainly made of bactericidal (alcohol, etc.) agents, antibiotics, and other materials, such as small packages of alcoholic agents, antibiotic films, and the like. Japan has used a large number of methods for placing small packets of alcohol in food packaging: it is filled with a food-grade alcohol absorbed in silica powder in a pouch made of a laminate of paper and EVA copolymer. The pouch weighs 0.6-6 grams and contains 0.5-3 grams of alcohol, which evaporates into the interior voids of the package. Alcohol vapor can inhibit the growth of different molds, 15 bacteria, and 3 kinds of spoilage bacteria, so that the shelf life of 5-20 times.
Antibiotics can be used to make antibiotic films as bactericidal materials. The active packaging made of them is coated with a layer of metal-bound zeolite on the inner surface of the antibiotic film. When the air passes through the film, it will produce ozone and kill microorganisms. The bread is packaged in this kind of film and it can be kept fresh for two weeks without mold. In addition, the simplest way to protect high-oil foods is to add antioxidants to the inner layer of the wax coating layer, but this has not been commercialized.
(5) Water absorption and water retention system The system is mainly composed of a layer of propylene glycol sandwiched between two layers of polyvinyl alcohol film, and then sealed around to form a packaging film, which is used to package fresh meat and fresh fish. Its moisture can be absorbed by propylene glycol and inhibited. Microbial reproduction. Packaging fresh vegetables with this film not only absorbs water, but also absorbs ethylene gas, utilizes the activity of live fresh materials (seafood, etc.) and the continuation of life.
3, fresh water live fresh live fresh water live fresh refers to freshwater fish and shrimp, the active packaging materials are container materials and soluble materials, soluble materials refers to the water to keep living fresh soluble materials.
The freshwater live-active packaging is listed as follows:
(1) The key to active packaging of live fish is to ensure that live fish must remain viable during transit and before sale or processing.
1) Hypnotic Packaging Technology This technique involves putting fish into water filled with 50% carbon dioxide and 50% oxygen gas. After about 25 minutes, when the fish is anesthetized, the fish is taken out for storage and transport. More than 30 After hours, put the fish in water again.
Hypnotic packaging technology can be carried out in live fish bags (plastic bags) or packaging containers (barrels, boxes, etc.), which solves the problem of difficult live fish survival in long-distance transportation.
2) Blindfold packaging technology This technique uses soaked paper to stick to the eyes of fish because the fish has dead glands behind the optic nerve and breaks after dehydration. Using this method, dead glands can still be maintained for a period of time, so as to preserve the activity of the fish.
In the dehydrated state, the life of the fish is free from worry. It is only necessary to maintain the humidity and temperature around the live fish, thus reducing the non-net weight of transportation and packaging.
3) Narcotic packaging technology This technology draws on the medical anesthesia techniques of the human body to make the fresh and numb in the state of numbness in transportation and storage. After a period of reviving, it still maintains vitality.
The specific approach is to add a certain amount of white wine in the pool or packaged water tank, so that the fish is in the “drunk” state, can also be directly in the fish nostril drops two drops of white wine, and then put the fish into breathable packaging (baskets, baskets, etc.) In the middle, a layer of damp cloth was added to keep moisture and humidity. The treated "live fish" could not die within three days, thus solving the problem of live fish packaging.
(2) Active packaging of live shrimp In the past, live shrimp were actually “dead” and then kept fresh. Now many countries and regions are conducting research and experiments to keep live shrimp alive before processing. This is live shrimp. Active packaging, Japan's research in this area has made major breakthroughs, and has been partially used in aquaculture.
Japan has researched specialized packaging technology that is specially used for long-distance transportation of live shrimp.
This technology uses ethylene as the inner layer of the packing box, using foamed styrene as the outer layer, and put 2 to 4 kg of crushed ice pieces between the double layers. The inner layer should prevent water leakage and the outer layer should be prevented from damage. In the inner tank containing live shrimp, the sterilized water will be filled with a certain amount of oxygen, and then sealed and shipped.
The experimental results show that the survival rate of live shrimp can be maintained at 90% or more within 24 hours even when the external temperature is as high as 40°C. When the outside temperature is low, the survival rate will be higher.
4, live fresh live active packaging In a sense, keep alive should be regarded as a special category of preservation, and is a more difficult technology. As far as the current scientific and technological conditions are concerned, the fact that the ice-warming preservation of transport capacity is large without water pollution is one of the development directions for the live-living transport of live fish in the sea.
How to realize the storage and transportation of live fish at high density has attracted more and more attention and is also the future direction of development.
(1) Principles of low-temperature keep-alive and related factors Marine fish, like other cold-blooded animals, will be significantly reduced in metabolism when the temperature of living environment is reduced. When the ambient temperature drops to its ecological ice temperature, the respiration and metabolism fall to the lowest point, at which point the fish is dormant. Therefore, in the area of ​​ice temperature, the appropriate cooling method and the storage and transportation conditions of the technology can be selected to allow the marine fish to survive for a period of time after escaping from the original living environment and achieve the purpose of keeping the transport.
There are many relevant factors that should be considered in the active packaging of live marine fish, including the performance of transportation and packaging equipment, the biological characteristics of marine fish, and environmental factors. The specific performance is: marine fish body traits, internal material composition, adaptability to the outside world, transport mode, temperature, shipping density, oxygen supply, metabolites, water quality, transportation time and so on. Water-free transportation should also consider cooling methods, holding procedures, and packaging materials.
(2) Commonly-used active packaging techniques There are many active packaging techniques for live sea fish. The current ones are more mature:
1) Anesthesia uses an anesthetic agent to inhibit the central nervous system, which can reduce the respiratory and metabolic intensity of fish and improve survival.
2) Low-temperature method According to the ecological ice temperature of aquatic animals, temperature control is adopted to make them semi-dormant or completely dormant, reduce metabolism, reduce mechanical damage, and prolong survival time. The method is widely used, such as fish, shrimp, crabs, shellfish and other live-keeping transport can be used.
3) Water-free method Since fish are cold-blooded animals and have hibernation characteristics, they use low-temperature methods to make fish hibernate, so that long-distance keep-alive transportation can be achieved. Japanese scholars once put the fish at an ecological ice temperature of about 7°C to keep the fish moist and keep it alive without water. The features of waterless keep-alive transportation are: no water, large amount of transportation, no pollution, and high quality of keeping, suitable for long-distance transportation.
5, plant active packaging materials and technology, vegetable sprouts, sprouts and flower food has become another consumer new fashion. In order to be able to eat off-site or cross-season vegetables, sprouts, flowers and other fresh vegetable foods, we must have a reliable packaging, this packaging must have the appropriate packaging materials and special packaging technology with it. To this end, we analyzed and studied plant active packaging materials and technologies.
According to the definition of active packaging, we can also refer to active vegetable packaging as an active packaging that keeps the plant alive or keeps the plant alive.
1 Plant active packaging materials Plant active packaging materials should have the following properties:
a. Water retention. The most characteristic feature of plant sprouts is that the surface is fresh and the area exposed to the air is large. It is easy to lose moisture in the air. In severe cases, the water absorption capacity of the sprouts is lost, resulting in moisture imbalance. Therefore, the packaging material should have water retention.
b. Inhibit nutritional loss. In the storage and transportation of sprouted vegetables will produce harmful substances due to metabolism, such as ammonia, more than phenol and ethylene, these substances will accelerate the loss of nutrients, so plant active materials should inhibit the production of harmful substances and preservation of sprout nutrition The function.
c. Ethylene absorption. Sprout vegetables produce large amounts of ethylene during storage after harvest. Ethylene accelerates the withering of vegetables and other plants, resulting in rot and discoloration. Therefore, it is important to absorb ethylene.
d. Cooling or insulation effect. Post-harvest sprouting vegetables increase their respiratory frequency during storage and consume large amounts of energy, resulting in fever, ultimately affecting their life span.
According to the above requirements for plant active packaging materials, a company in Japan researched and introduced packaging materials for plant sprouts, called packaging materials for fresh-keeping and cold-keeping.
The packaging materials for low-temperature transport of flowers and fresh foods require heat insulation, water resistance, and heat regulation. In the past, foamed styrene materials were used to fix metal films of different sizes and shapes, but they were used in corrugated paper. In this case, there are disadvantages such as poor heat insulation and difficulty in keeping fresh.
The packaging material used for fresh-keeping and cold-keeping is made of a synthetic resin foamed film made into a corrugated shape, and a central portion of the packaging material is pasted with a plate liner to obtain a new material required. The packaging container manufactured by using this material has the following characteristics: (1) Compared with ordinary corrugated paper, it has high heat insulation; (2) has moderate air permeability; (3) has good water resistance; (4) can be folded And the printability is good; (5) The container can be used repeatedly and eventually lost its value.