Application of vacuum in food packaging and freeze drying industry

In the past twenty years, the technology of food preservation using vacuum atmosphere has developed rapidly.Because this kind of packing not only has exempted from oxygen make food not easy to rot, stick put oneself and inflatable packaging can be not affected by insects damage and inhibit the growth of mold, can improve and extend the characteristics of food preservation and storage time, and most packaging equipment has simple structure, convenient operation, low price, the plastic packaging materials of low cost, beautiful and easy, easy to popularize.There are many kinds of vacuum-packed food, such as pickle, turnip, kelp, sausage, braised chicken, roasted duck, soybean products, milk powder, malted milk and so on.

Due to the long time in the intermediate link from harvest to sale of fresh products, serious loss is easy to raise the selling price, while the promotion of vacuum packaging technology will reduce the price of fresh products and the cost of cold storage, so as to ease the cycle between supply and demand.Therefore, vacuum fresh-keeping will become a market with great potential and be active in people's life.

Vacuum freeze-drying technology first appeared in the early 20th century and has developed rapidly in recent years.This is because it has many advantages compared with the usual hot drying, hot air drying, infrared drying and high-frequency drying.The process of freeze-drying is to freeze the dry material first and then vacuum, so that the frozen water in the material will not pass through the liquid state and directly sublimate to remove.Therefore, the freeze-dried products can not only show the porous state and keep the original shape, but also recover easily after adding water, and the low-temperature drying can prevent the thermal decomposition of materials.At the same time, because the materials dried in a vacuum atmosphere are free from oxidation, the physical, chemical and biological properties of the dried products can be completely unchanged.The application of vacuum freeze-drying is expanding year by year