Vacuum packaging not only has the characteristics of eliminating oxygen, making food not easy to rot and deteriorate, not being harmed by insects, but also inhibiting mold growth, improving and prolonging food preservation and storage time, and most packaging equipment is simple in structure, easy to operate, and inexpensive. Plastic packaging materials are low-cost, beautiful, and easy to popularize. Due to the long intermediate links in the process of fresh products from harvesting to other sales, serious losses can easily increase the sales price. The promotion of vacuum packaging technology will reduce the price of fresh products and refrigeration costs, thereby easing supply and demand. Between spears. Therefore, vacuum preservation will surely become a market with great potential and be active in people's lives.
Vacuum freeze-drying technology first appeared in the early twentieth century, and has developed rapidly in recent years. This is because it has many advantages compared with the usual heat drying, hot air drying, infrared drying, and high-frequency drying. Because the process of freeze-drying is to freeze the dried material first, and then vacuumize it, so that the water in the material that has been frozen into ice is directly sublimated and removed without going through the liquid state. Therefore, the freeze-dried product can not only maintain the original shape in a porous state, but it can be easily restored to its original state after adding water, and low-temperature drying can also prevent the thermal decomposition of the material. At the same time, because the materials dried under a vacuum atmosphere are exempted from oxidation, the physical, chemical, and biological properties of the dried products can be completely unchanged.