New Progress in Fresh-keeping Packing of Vegetables and Fruits (Part Two)

Corrugated cardboard boxes with thermal insulation. At low temperatures, not only the respiration of vegetables and fruits is weakened, but also the activity of bacteria is greatly reduced. Therefore, low-temperature storage is the most effective means and is the development direction of maintaining the freshness of food.
Corrugated cardboard boxes with thermal insulation have a good fresh-keeping function. This type of corrugated carton is made by laminating a composite resin and an aluminum evaporated film in a conventional carton, an outer package, or adding a foamed resin to a paper core. This type of corrugated box has excellent heat insulation and can prevent the temperature of the fruits and vegetables themselves from increasing during the circulation.
Corrugated box with control of gas function. As mentioned above, adjusting the stored gas composition, humidity, and other conditions will also achieve a definite preservation effect, which is an important aspect of the preservation technology.
Corrugated box with control of gas function. The corrugated box with the function of controlling the gas is a porous powder that can adsorb ethylene gas in the inner lining of the carton and the outer lining, or in the papermaking stage. This corrugated box has gas barrier properties to prevent the evaporation of moisture from fruits and vegetables and achieve the effect of controlling the content of gas, thereby maintaining the freshness of fruits and vegetables.
Fresh-keeping sheets, preservatives and cold storage agents In order to enhance the freshness of fruits and vegetables, in the use of the above-mentioned packaging materials, Keli can have specific functional substances, such as fresh-keeping sheets, preservatives and cooling agents.
Fresh food sheet. The single packaging of fruits and vegetables uses plastic platters and thin film composite products, so the functional sheet placed on the platter body or above has a freshness-keeping function. These sheets often have one or more functions such as humidity control, dew proofing, ethylene gas absorption, and antibacterial. Among them, moisture-adsorption and water-absorption is a multi-layer structure composed of a superabsorbent resin and a non-woven fabric, a thin paper, and a water-absorbing polymer; the absorption of ethylene gas mostly utilizes the porosity of activated carbon; the antibacterial property is due to the addition of a sheet Silver zeolite and other inorganic substances with antibacterial properties or antibacterial ingredients extracted from plants.
preserver. Since the absorption of the functional film that absorbs ethylene gas is limited by the amount of use, preservatives for adsorbing ethylene gas are widely used. Packaging fruits and vegetables together with preservatives can achieve a certain purpose of inhibiting ethylene gas. Currently used preservatives often use oxidants such as potassium permanganate, gas adsorption buttons such as activated carbon and mineral powder, and palladium catalysts.
Coolant. Since the preservation of fruits and vegetables at low temperatures is beneficial to the preservation of freshness, the use of cold storage materials has become an important means in preservation technology. An elastic gel-like material containing a polymer obtained by polymerizing and crosslinking polyacrylic acid as a main component is a high-performance cold storage material. If you use it with a heat shield, it works better.
Other preservation methods and technologies New preservation trays. The fresh-keeping tray is obtained by heating the continuous extruded original plate (thermoplastic resin sheet) by vacuum forming and stamping. In addition to preventing fresh food from being damaged, the use of a tray also has a certain degree of thermal insulation. The so-called new tray is a molded product obtained by adding a functional film or a long fiber nonwoven fabric to an original sheet. This kind of tray adds functions such as adjusting humidity, controlling gas content, preventing mold propagation, etc. on the basis of the original function, so it can maintain the freshness of vegetables and fruits. In addition, the tray can reduce the change in the package size caused by absorbing moisture.
Radioactive sterilization. In order to reduce the influence of pathogenic microorganisms on the freshness of fruits and vegetables during storage and transportation, the vegetables and fruits may be first sterilized by radiation after picking, and then packaged and transported. At present, the United States and South Africa and other countries adopt a certain intensity of radiation treatment under a certain intensity of radiation. (Finish)