Abstract: Due to the food itself and its processing technology, the barrier properties of packaging materials before and after packaging foods are likely to change. This paper takes the mustard packaging material as an example to study the change of oxygen barrier performance before and after contact with mustard. Through the introduction of the test principle, equipment parameters, application scope and test process, it provides reference for the rational selection of food packaging. Key words: packaging materials, barrier properties, oxygen permeation, differential pressure gas permeation, mustard 1 , meaning The continuous development of food packaging types and technologies is one of the key factors for food to be stored for a long time and to achieve a wide range of circulation. Food packaging can easily achieve the relative independence of content and environment, and reduce the impact of gases in the environment on food. Most food packaging materials are high molecular polymers. Different types of polymers have different tolerances to acids, alkalis, oils and other ingredients in food. In addition, foods are often sterilized by high temperature, cooking, high pressure or irradiation after packaging. In the link, these factors are likely to affect the performance of polymer materials, and the properties of materials before and after packaging foods will vary. If the performance of the material after packaging the food is degraded, it will affect the expected quality of the packaging material. Therefore, timely detection of the performance changes of the materials before and after packaging food is of great significance for screening suitable packaging materials and improving product quality. Barrier performance is an important factor affecting the suitability of packaging materials. This paper tests the barrier properties of materials before and after packaging foods. 2 , test samples As a common pickled food, mustard contains a certain amount of juice, and the finished packaging will undergo a specific sterilization process. At the same time, the higher oxygen barrier performance is the basic performance of the mustard packaging material to prevent the quality problems of microbial over-standard and rancid in the shelf life of the mustard. Therefore, this paper takes the mustard packaging material as the test sample to test the change of oxygen permeation before and after packaging the mustard. Figure 1 Example of common mustard packaging form 3 , the test basis At present, the detection methods of oxygen permeation of film and sheet packaging materials mainly include two methods: equal pressure method and differential pressure method. The method is based on the principle of differential pressure method. The reference method standard is GB/T 1038-2000 . Pressure difference method with sheet gas permeability test method . 4 , test equipment In this paper, the VAC-VBS differential pressure gas permeation instrument is used as the test equipment. The equipment is independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd. Figure 2 VAC-VBS differential pressure gas permeation meter 4.1 Test principle The principle of differential pressure method refers to the principle method of maintaining a certain pressure difference on both sides of the sample during the test. The sample clamped in the test chamber divides the test chamber into upper and lower chambers, the upper chamber is filled with a certain amount of oxygen, and the lower chamber is vacuumed to form a low pressure environment, so that a certain pressure is formed on both sides of the sample. difference. Under the action of pressure difference, oxygen permeates from the upper chamber through the sample into the lower chamber, causing the change of the pressure in the lower chamber. By monitoring the change of the pressure in the lower chamber with time, the oxygen permeation amount of the sample can be obtained. parameter. 4.2 Equipment parameters 4.3 Scope of application (1) This equipment is suitable for gas permeability testing of various films and sheets. Films include various plastic film, paper-plastic composite film, co-extruded film, aluminized film, aluminum foil, aluminum foil composite film and other film-like materials; sheet materials include various engineering plastics, rubber, building materials and other sheet materials, such as PP Sheet, PVC sheet, PVDC sheet. (2) This equipment can also be extended to aerospace materials, paper and paperboard, paint film, fiberglass cloth, glass fiber paper, cosmetic hose sheets, various rubber sheets and other materials for gas permeability testing. (3) This equipment is suitable for the permeability test of various gases, such as oxygen, carbon dioxide, nitrogen, helium, air, etc. (4) The number of devices to meet national and international standards, such as ISO15105-1, ISO2556, GB / T1038, ASTM D1434, JIS K7126-1, YBB00082003. 5 , the test process 5.1 Test of raw material bag samples of mustard packaging materials (1) Three samples having a diameter of 80 mm were cut out from the surface of the sample from the unpacked mustard . (2) uniformly apply a layer of vacuum grease on the periphery of the three test chambers, and place a piece of filter paper on each test area, paste the samples on the three test chambers, and gently press the test chamber and the sample contact area. Remove the air bubbles between the two, close the upper chamber and clamp them separately. (3) Set the sample name, test mode, vacuuming time, test temperature and other parameter information on the control software of the equipment, turn on the oxygen gas source, click the test option, turn on the vacuum pump, and start the test. Test equipment according to the set parameters, test results show the average of three specimens after the test. 5.2 Testing of samples after packaging mustard (1) Remove the mustard from the inside of the sample package, cut the sample along the heat-sealed portion, gently wash the juice on the surface of the sample with water, and then dry it naturally. The cleaning process should prevent creases on the surface of the sample. (2) Test the dried samples according to the procedure in 5.1 . 6 , test results The oxygen permeation test value of the unpackaged mustard sample was 46.3201 cm 3 /(m 2 ·24h·0.1MPa) , and the oxygen permeation amount of the sample after the packaged mustard was 60.4467 cm 3 /(m 2 ·24h·0.1MPa) . 7 , conclusion Food ingredients and sterilization processes may affect the performance of packaging materials. Therefore, comparing the performance of materials before and after packaging food is an important basis for judging the compatibility of food and packaging materials. In this paper, the change of oxygen permeation of samples before and after packaging mustard was tested. The equipment was easy to operate, the degree of intelligence was high, and the test results were accurate and reliable. The oxygen permeation of the sample after the mustard was increased significantly, and the oxygen barrier performance decreased. In addition to oxygen transmission, the equipment can also be used for packaging materials to test the gas barrier properties of air, nitrogen, carbon dioxide, helium, sulfur hexafluoride, etc., and has high test efficiency and high cost performance. Jinan Languang Electromechanical Technology Co., Ltd. is a high-tech enterprise specializing in R&D, production and packaging inspection services for packaging inspection equipment, and understand related testing equipment and services . The more you understand, the more you trust! Labthink is looking forward to strengthening technical exchanges and cooperation with enterprises and institutions in the industry!
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