How to verify the quality of food packaging

Much of the discussion in food packaging about how to extend the shelf life of a product has shifted from the handling of the product itself to the packaging system. For food packaging, better oxygen resistance, water resistance and packaging air tightness are essential requirements. These requirements can be verified by oxygen infiltration, water vapor infiltration, all sealing and heat sealing functions of the food packaging.

Oxygen permeability: Oxygen affects food in four main aspects: color change, flavor change, oil/fat change and microbial change. Mastering the oxygen pass quantity and pass coefficient of food packaging package data can effectively help enterprises choose packaging data and provide scientific basis for maintaining product quality and preserving products. The test principle is to calculate the air permeability and air permeability at both ends of the flexible packaging film sample under a certain temperature and humidity by measuring the change of the gas pressure at the low pressure side of the sample.

Water vapor penetration: If the water of the product itself oozes from the inside of the packaging film through water vapor, or the product absorbs water vapor from the outside of the packaging, the flavor, organization and content of the product will change. Therefore, it is necessary to accurately grasp the water vapor penetration and permeability coefficient of the plastic film packaging data. The principle of water vapor passage detection is to make one side of the plastic film sample at a certain temperature to maintain a stable and full steam pressure, the other side to keep monotonous. The full water vapor passes through the sample into the monotone side, and the water vapor permeability and permeability of the sample are obtained by measuring the change of the evaporation of distilled water in the permeable cup as it decreases at any time. Maintaining product quality and preventing the natural loss of quantitative products is the key to the passage amount and passage coefficient of water vapor.

Overall sealing: Assuming that the sealing of the package is not good, oxygen and water vapor can directly enter the package to degrade and transform the food. There are many ways to check the seal function. The commonly used method is to use the sealed test instrument and vacuum principle, which are respectively -30kpa, -50kpa, -70kpa and -90kpa according to the national standard for a certain time, to check whether the bag leaks in the experiment and whether the bag recovers after the experiment. In order to better control the airtightness of packaging and extend the shelf life of products, it is necessary for manufacturers to effectively measure the sealing function of packaging under different pressures.

Heat sealing function: Heat sealing function is an important parameter that affects the overall sealing performance of packaging. Assuming that the heat sealing parameters are improperly set and the strength of the heat sealing part is thin, the bag in the heat sealing part will simply break under the impact of the contents or external kneading. The three elements of heat sealing process are heat sealing temperature, pressure and time, among which temperature is the main one. According to the different requirements of plastic packaging data and data bag movement conditions, it is necessary to coordinate to obtain good heat sealing quality and then ensure the sealing performance of all packages.