Research and development trend of fresh-keeping pa

2022-09-21
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Trends in research and development of fresh-keeping packaging for vegetables and fruits

with the continuous growth of economic income, people's dietary life has changed from a single type of food and clothing in the past to a diversified nutritional type now. At present, under the advocacy of the new concept of nutrition by experts, vegetables and fruits are generally favored, and the consumption is increasing. Due to the regional and seasonal differences in the production of fruits and vegetables, its circulation has also increased. In order to maintain the freshness of vegetables and fruits in the process of storage, transportation and sales, relevant enterprises and scientific research institutions have increased research and development in recent years. Fujian (Longyan) Rare Earth Industrial Park, located in the suburb of Changting County, has launched a number of packaging materials with fresh-keeping functions. There are mainly:

functional fresh-keeping film

although the traditional film can play the role of packaging and has a certain fresh-keeping effect, it obviously can not meet the fresh-keeping needs of the modern market. Therefore, a large number of new fresh-keeping films have been developed. These functional fresh-keeping films not only have the effect of preventing water evaporation in the past and recently simply controlling gas, but also further improve the freshness of vegetables and fruits. They are -

ethylene adsorption film. Ethylene adsorption film is to remove harmful ethylene gas, and mix gas adsorption porous substances into the plastic film, such as tuff, zeolite, quartzite, silica, clay ore. during the inspection of oil leakage, micro powders such as stone powder, most of which can adsorb ethylene or block far-infrared radiation. At present, in foreign countries, tuffaceous films are used more, mainly adding silicate ceramics, and the effect is better

anti dew film the fresh-keeping film for vegetables and fruits is generally made of low-density polyethylene, polypropylene, polystyrene, ethylene vinyl acetate copolymer and polyvinyl chloride resins with high gas permeability. The water vapor produced by the vegetables and fruits packed with these films is easy to condense on the inner surface of the film, which not only reduces its transparency, but also accumulates water droplets, which makes bacteria proliferate quickly and causes the corruption of vegetables and fruits. The anti dew film is used to treat the inner surface of the above polyethylene, polypropylene and other materials with interfacial active agent, so that it can absorb excess water and appropriately maintain the humidity in the package, so as to achieve the purpose of corrosion prevention and preservation. Fatty acid esters can be used as both food additives and anti dew agents

antibacterial film antibacterial film is to mix antibacterial silver zeolite into the film. Silver zeolite is the mixture of antibacterial silver and sodium ion replacement in zeolite crystal structure or silver ion and synthetic loose zeolite with aluminum and silicon as raw materials. PE, PP and PS are mainly used as base materials. This film can inhibit the reproduction of bacteria to a certain extent and play a role in keeping fresh

functional fresh-keeping corrugated box

low temperature storage of corrugated box with heat insulation function is an effective means of food preservation at present. Corrugated boxes with heat insulation function are lined with composite resin and aluminum evaporation film in traditional boxes and outer packages, or foam resin is added to the paper core. It has excellent heat insulation, prevents the temperature of vegetables and fruits from rising during circulation, and achieves the purpose of fresh preservation

corrugated box with gas control function. This kind of corrugated box is sandwiched with fresh-keeping film in the inner and outer lining of the box or mixed with porous powder that can adsorb ethylene gas in the papermaking stage, making it gas barrier. Prevent partial evaporation of water in vegetables and fruits, and achieve the effect of controlling gas content, so as to maintain the freshness of vegetables and fruits

other fresh-keeping packaging materials and technologies

fresh-keeping sheet the single packaging of vegetables and fruits uses the composite products of plastic shallow plate and film, so the functional sheet placed at the bottom or above the shallow plate has the effect of fresh-keeping. These sheets have one or more functions, such as humidity regulation, dew proof, ethylene gas absorption, antibacterial, etc. Among them, humidity control and water absorption is a multi-layer structure composed of super absorbent resin, non-woven fabric, tissue paper and water absorbent polymer; Absorption of ethylene gas is mostly based on the porosity of activated carbon; Antibacterial property is due to the addition of inorganic substances with antibacterial properties such as silver zeolite or antibacterial ingredients extracted from plants

preservatives are widely used because the absorption of functional films that absorb ethylene gas is limited by the amount. Packaging vegetables and fruits together with preservatives can achieve a certain purpose of inhibiting the production of ethylene gas. At present, oxidants such as potassium permanganate, gas adsorbents such as activated carbon and mineral powder are often used as preservatives

cold storage agent because the preservation of vegetables and fruits at low temperature is conducive to maintaining freshness, the use of cold storage materials has become an important means of fresh-keeping technology. The elastic gel like material obtained by polyacrylic acid polymerization and crosslinking is a kind of high-performance cold storage material. If it is used with chrome oxide grinding paste, the effect is better

new fresh-keeping tray fresh-keeping tray is obtained by heating the continuously extruded raw plate (thermoplastic resin sheet) and forming it by vacuum molding and stamping. In addition to preventing fresh food from being damaged, the tray also has a certain degree of heat insulation. The so-called new tray is a molded product made by adding functional films or long fiber non-woven fabrics to the original board. On the basis of the original function, this tray increases the functions of adjusting humidity, controlling gas content, preventing mold propagation, etc., so it can maintain the freshness of fruits, and this tray can reduce the change of package size caused by absorbing water

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