Good for preservation
The main methods for fruit preservation are maintaining low temperature, controlling water evaporation, regulating gas environment, removing ethylene gas, sterilization and antibacterial, etc., mainly using functional plastic wrap, new corrugated carton, functional preservatives and other materials.
A large number of new cling films have appeared on the market, which not only has the function of traditional films to prevent evaporation of water and simple control of gases, but also further improves the freshness of fruits. For example, the dew-proof film can treat the inner surface of the packaging material by using a surfactant and absorb the water vapor generated by the shrinkage of the fruit, so that the humidity in the package can be properly maintained to achieve the purpose of preservation. Another example is an ethylene adsorption film in which plastic gas films (especially LDPE) are mixed with gas-absorbing porous materials such as tuff and zeolite, quartz stone, and silica fine powder, which can adsorb ethylene or block far-infrared radiation.
Fresh-keeping corrugated cartons mainly have two kinds of heat insulation and control gas functions. The former is to laminate composite resin and aluminum evaporated film in the traditional carton and outer packaging, or to add foaming resin to the paper core, which can prevent the temperature of the fruit itself from increasing during the circulation. The latter is a porous powder that can absorb ethylene gas in the inner lining of the carton and the outer lining, or is mixed with porous powder that can absorb ethylene gas. It has a gas barrier property and prevents the moisture of the fruit from evaporating.
In order to enhance the preservation effect of fruits, at the same time as using the above packaging materials, it is also possible to add substances with specific functions such as fresh-keeping sheets, preservatives and cooling agents. The preservative sheets have one or more functions such as humidity control, dew proofing, ethylene gas absorption, and antibacterial; the preservatives are most widely used for absorbing ethylene gas; the cold accumulating agent is a kind of polyacrylic acid polymerized and linked together. The resulting polymer is an elastic gel-like material having a main component, which can effectively maintain the freshness of fruits at low temperatures.
