How can the sealing of baking packaging film and bags effectively isolate air?
Publish Time: 2025-02-17
To effectively isolate air from baking packaging film and bags, we can start from the selection of film bag materials, packaging process and subsequent storage.High barrier materialsBaking packaging film and bags give priority to plastic materials with high barrier properties, such as ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), etc. Among them, EVOH has an excellent barrier effect on oxygen, which can effectively prevent baked goods from oxidizing and deteriorating due to contact with oxygen. For example, some high-end bread and cake packaging often use film bags containing EVOH. In addition to having good oxygen barrier properties, PVDC can also block water vapor, which can keep the moisture content of baked goods relatively stable and extend the shelf life.Multilayer composite filmThe multilayer composite film combines the advantages of different materials and can significantly improve the comprehensive barrier properties of the film bag. For example, the heat sealing properties of polyethylene (PE), the high strength and barrier properties of nylon (PA), and the high barrier properties of aluminum foil are compounded together. This composite film can effectively block the entry of oxygen, water vapor and light, providing more comprehensive protection for baked goods. Common composite structures include PA/PE, PET/AL/PE, etc., which are widely used in the packaging of various baked goods.Heat sealing processHeat sealing is the key link to ensure the sealing of film bags. According to the characteristics of the film bag material, the heat sealing temperature, pressure and time should be accurately controlled. Too high temperature will cause the film bag material to melt excessively, resulting in perforation or damage, affecting the sealing; too low temperature may make the heat seal weak and prone to air leakage. For example, for common PE film bags, the heat sealing temperature is generally controlled at 120-180℃, the pressure is maintained at 0.2-0.4MPa, and the heat sealing time is about 1-3 seconds.Vacuum packagingThe air in the film bag can be effectively removed by using vacuum packaging technology. First, put the baked food into the film bag, and then use the vacuum packaging machine to extract the air in the bag, and then heat seal it after forming a certain vacuum degree. This can greatly reduce the contact between food and oxygen, and slow down the oxidation and deterioration of food. For some baked foods such as meat floss and nuts, the shelf life can be significantly extended after vacuum packaging.Nitrogen filling packagingAfter the air in the film bag is extracted, inert gas such as nitrogen is filled in and then sealed. Nitrogen has stable chemical properties and can prevent food oxidation, mildew and insect pests. Nitrogen filling packaging can also keep the film bag full, protect the appearance of baked food, and avoid extrusion damage during transportation and storage. For example, some fragile baked foods such as puffs and egg tarts can be better maintained in their integrity by nitrogen filling packaging.Sealing performance testingDuring the packaging production process, the sealing performance of the film bag should be tested regularly. Commonly used testing methods include pressure method and vacuum method. The pressure method is to fill a certain pressure of gas into the sealed film bag, and then detect the pressure change to determine whether the film bag is leaking. The vacuum method is to place the film bag in a vacuum environment, observe the deformation of the film bag and whether bubbles are generated to determine its sealing effect.Quality ControlEstablish a strict quality control system to monitor the entire process of raw material procurement, production and processing, and packaging of film bags. Ensure that each film bag meets the sealing performance requirements, and deal with unqualified products in a timely manner to avoid entering the market.Storage EnvironmentBaking packaging film and bags should be stored in a dry, cool, and ventilated environment after packaging, avoiding high temperature, high humidity, and direct sunlight. High temperature will reduce the performance of the film bag material and affect the sealing; high humidity environment may cause the film bag to get damp and reduce its barrier performance. For example, the storage temperature should be controlled at 20-30℃, and the relative humidity should be maintained at 40%-60%.Transportation ProtectionDuring transportation, appropriate protective measures should be taken to prevent the film bag from being squeezed, collided, and rubbed. Special packaging boxes or pallets can be used to fix and protect baked goods. At the same time, avoid contact with sharp objects to avoid scratching the film bag and destroying its sealing.
