Because the main objects of food packaging film are diverse and have different requirements, the content of packaging basically covers the range of composite packaging bags, from raw to cooked, from low temperature to high temperature, from perishable fresh fruits to hard nuts, from vacuum packaging bags to inflatable packaging bags.
(1) Separation requirements: most foods are rich in oil and are easy to oxidize and deteriorate. So they have strict requirements for oxygen resistance, and they also have high requirements for the increase or decrease of moisture in food packaging film.
(2) Water activity: All foods contain a specific amount of water. After the selection of packaging materials, the moisture content of food changes little if the processing conditions and formula of food remain unchanged. When conditions change, it will directly affect the original water activity value of food, and water is one of the important factors causing food deterioration. Microbes can grow as long as they have a specific water content. Different materials and methods should be used for different foods with different water content.
(3) Vacuum requirements: vacuum packaging is isolated from oxygen and moisture-proof, which can not only ensure the quality of materials, but also make the appearance of goods beautiful and generous.
