Abstract: Protein film is a kind of green environmental protection packaging material. It has broad development space under the form of advocating environmental protection. In this paper, taking a wheat protein film sample as an example, the Labthink OX2/230 oxygen transmission rate test system was used to test its oxygen transmission rate, which overcomes the fragile characteristics of the protein film, and passes the test principle, equipment parameters and A brief introduction to the scope of application, test procedures, etc., provides a practical method for testing the oxygen barrier properties of protein film samples.
Key words: oxygen transmission rate, oxygen permeation test system, oxygen barrier property, protein membrane, temperature, humidity
1, meaning
Protein membrane, as its name suggests, is made from animal protein isolates or plant protein isolates, and is added with additives such as plasticizers and cross-linking agents. Common protein membranes include whey protein membrane, wheat gluten protein membrane, and soy protein isolate. Membrane, zein film, peanut protein isolate film, etc., depending on the type and application field of the protein film, the film formation method includes casting film formation, coating or spray film formation, extrusion film formation, and the like. Protein film is an edible and degradable film used for product packaging, especially food packaging, which can effectively solve the food safety hazard caused by plastic packaging and reduce the environmental burden of plastic packaging waste. Therefore, protein The application and research and development of membrane materials have become a research hotspot. In view of the fact that oxygen is one of the causes of quality problems such as oxidative deterioration and mildew in foods, oxygen barrier performance is an important performance that protein membranes cannot be ignored as food packaging. Due to the characteristics of its structure, the protein film is usually sensitive to humidity. When the ambient humidity is low, it is easy to lose water and break. When the humidity is high, it is easy to absorb water and stick, so during the oxygen permeability test. Control of test conditions is particularly important.
2, test samples
This test uses a wheat protein membrane developed by a company as a test sample.
3. Testing basis
At present, there are two methods for testing the oxygen transmission rate: the equal pressure method and the differential pressure method. In order to prevent the sample from being damaged due to the unequal pressure on both sides, the equal pressure method is used for this test, and the corresponding standard is GB/ T 19789-2005 "Colour meter test for plastic film and sheet oxygen permeability test of packaging materials".
4, testing equipment
The test equipment used in this test is the OX2/230 oxygen transmission rate test system, which is independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd.
Figure 1 OX2/230 oxygen transmission rate test system
4.1 Principle of the test
The isobaric method, also known as the coulomb meter detection method, describes the gas pressure on both sides of the sample, and the latter describes the detection method used. During the test, the sample is clamped between the test gas chamber and the test chamber, the high-purity oxygen flows in the test gas chamber, and the carrier gas flowing in the test chamber is a high-purity nitrogen gas of equal pressure. According to the principle of gas diffusion, oxygen Under the action of the concentration difference, the test gas chamber penetrates into the test chamber through the sample, and is carried by nitrogen to the coulometer sensor for oxygen concentration analysis, thereby obtaining parameters such as oxygen permeability of the sample.
4.2 Equipment parameters
The test range of the film sample is 0.01~6500cm3/(m2·d), the resolution is 0.001cm3/(m2·d), and the test range of the container sample is 0.0001~60cm3/(pkg·d), the resolution It is 0.00001 cm3/(pkg·d).
Three identical or different samples can be tested at the same time. The system can support up to 10 instruments in parallel connection, and establish an efficient system for simultaneous testing of 30 samples.
The test temperature control range is 15~55°C, and the temperature control accuracy is ±0.1°C.
The test humidity control range is 0% RH, 35% RH~90% RH, and the humidity control accuracy is ±1% RH.
Wide range, high precision temperature and humidity control range, both sides of the sample can be humidified to achieve the test under different temperature and humidity conditions.
The world's leading pressure compensation technology guarantees high precision and repeatability of test results.
It can be combined with the water vapor transmission rate test system to form a hybrid test system, which is controlled by a computer to achieve simultaneous oxygen and water vapor transmission rate testing.
Support LystemTM laboratory data sharing system to manage test results and test reports.
4.3 Scope of application
The device is suitable for testing the oxygen transmission rate of various types of samples, including films, such as various plastic cover films, plastic composite films, paper-plastic composite films, co-extruded films, aluminized films, aluminum foils, aluminum-plastic composite films, etc. Membrane materials; sheet materials, various engineering plastics, rubber, building materials and other sheet materials, such as PP sheet, PVC sheet, PVDC sheet, etc.; containers, all kinds of plastic, rubber, paper, paper-plastic composite, Oxygen transmission rate test of bottles, bags, cans, boxes and barrels made of glass, metal, etc., such as Coke bottles, peanut oil barrels, Tetra Pak packaging, vacuum packaging bags, metal three-cans, plastic cosmetic packaging, toothpaste soft Tube, jelly cup, yogurt cup, etc. Can meet ISO15105-2, GB/T19789, ASTM D3985, ASTM F2622, ASTM F1307, ASTM F1927, JIS K7126-2, YBB00082003 and many other national and international standards.
5, the test process
(1) A sample was taken from the wheat protein film sample by a sampler. The three cut samples were individually clamped into the three permeation cells of the apparatus.
(2) Set the test parameters such as test temperature, humidity, sample name, thickness, etc., select the test mode, click the test option, and the test starts. In order to prevent the sample from chipping during the test, the temperature and humidity of this test were set to 23 ° C and 60% RH, respectively. Adjust the gas flow so that the humidity in the permeation tank reaches the set value.
(3) After the test is over, the device automatically displays the test results of the three samples. Purge the tubing and turn off the device.
6, test results
The oxygen permeation of the three samples of the wheat protein film sample tested in this test were 7651.3241 cm3/(m2·24h), 7670.0569cm3/(m2·24h), 7656.3753cm3/(m2·24h), and the oxygen permeation of the sample. The average value of the three test results was 7659.2521 cm3/(m2·24h).
7. Conclusion
In the test of the oxygen permeability of the protein membrane, the control of the test conditions is particularly important, otherwise it is prone to fragmentation, resulting in failure of the test. The OX2/230 oxygen transmission rate test system can obtain three test results in one test, which greatly improves the test efficiency. The test results are reproducible and stable, and can accurately reflect the oxygen permeability of the tested protein film samples. Test conditions, the sample was not damaged during the test. Jinan Languang Electromechanical Technology Co., Ltd. is a high-tech enterprise specializing in the production, research and development and testing services of packaging testing equipment. The testing equipment developed so far covers the barrier properties of materials such as oxygen, nitrogen, water vapor and carbon dioxide. Tests for impact resistance, puncture resistance, friction properties, smash resistance, sealing performance, evaporation residue, solvent residue, etc., can serve food, pharmaceutical, chemical, daily chemical products, automotive, packaging materials manufacturers and many other fields. Learn about the relevant testing equipment and testing services, you can log in to view. The more you understand, the more you trust! Labthink is looking forward to enhancing technical exchanges and cooperation with users in various industries.
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