Abstract:Yogurt is convenient to carry and easily digested and absorbed by the human body, making it a common nutritional food in daily life. But due to its high content of fat and protein, it is easily oxidized by oxygen components in the air and undergoes spoilage. So, in order to ensure that yogurt products are not prone to quality problems during their shelf life and to achieve a longer shelf life, the yogurt cups used must have high oxygen barrier properties. Generally, the lower the oxygen permeability, the better the oxygen barrier properties. This article mainly introduces the testing method and principle of the oxygen resistance of yogurt cups, and details the technical information such as the testing process, providing a solid reference for related industries.

KeywordsYogurt, dairy products, yogurt cups, oxygen barrier properties, barrier properties, oxygen permeability, oxidative deterioration, container oxygen permeability testing, oxygen permeability testing system

Test significance:

yogurtIt is a high nutrient dairy product that adds a special variety of beneficial bacteria (i.e. fermentation agent) to fresh milk that has been pasteurized, undergoes fermentation, and is then cooled and filled. Yogurt contains a large amount of nutrients such as protein, fat, vitamins, and beneficial bacteria, and is easily digested and absorbed by the human body. Due to processing needs and convenience for consumers to consume, most yogurt products are packaged in cups, and the vast majority of yogurt cups used are made of plastic materialsPPThePSThePEMainly refers to the common white plastic cup, but also includesPE/paper/PEA paper-based yogurt cup made of composite material. At the same time as filling yogurt, yogurt cups also need to be sterilized in different ways to ensure that yogurt is not easily spoiled by other harmful bacteria. In order to prevent the quality problems of oxidation and deterioration of yogurt, the oxygen resistance requirements for yogurt cups are also high. If their oxygen resistance is poor, yogurt is easily oxidized by oxygen that penetrates from the outside, resulting in quality problems such as mold growth, cup swelling, and tofu residue.

The thicker the plastic yogurt cup or the higher the density of the material used, the higher the barrier properties of the yogurt cup, including oxygen and moisture resistance. How to monitor the oxygen barrier of yogurt cups to the outside world and whether the oxygen barrier of yogurt cups meets the quality requirements of the labeled shelf life, it is necessary to rely on detecting the oxygen permeability index. The lower the permeability, the higher the oxygen barrier. This article is based on a professional oxygen permeability detection instrument used for testing containers, and provides a detailed introduction toPPThe testing process and principles of oxygen permeability for yogurt cups made of materials provide powerful technical references for the yogurt cup production and use industry.

Detection method:

Internationally, there are two methods for testing oxygen permeability: isobaric method and differential pressure method. The isobaric method uses a Coulomb electric sensor to absorb oxygen that passes through a thin film and convert it into a current signal to calculate the oxygen permeability. Its detection limit is low, and it can accurately test the oxygen permeability of high barrier materials. In addition, the isobaric method can overcome the inevitable impact of the differential pressure method on plastic containers due to the pressure difference on both sides, thereby expanding the oxygen permeability of the testing container. Therefore, when testing the oxygen permeability of container packaging materials both domestically and internationally, the isobaric method (i.e. Coulomb electric sensor method) is mostly used for testing. However, in recent years, relevant instrument manufacturing companies have gradually solved the impact of pressure difference method on containers and developed gas barrier properties that can test low barrier packaging containers (i.e. with high gas permeability).

The oxygen permeability test of containers using the isobaric method at home and abroad mainly followsASTM F 1307There is currently no relevant domestic standard for the international standard of "Determination of Oxygen Transfer Rate of Dry Solid Packaging by Electricity Consumption Sensor". We will adoptLabthinkDeveloped independently by Languang CompanyC230HOxygen permeability testing system combined with the above standardsPPConduct oxygen permeability test on yogurt cup samples made of materials.

1Experimental instruments

C230HOxygen permeability testing system（LabthinkLanguang adopts excellent fluid mechanics and thermodynamic design testing integrated block technology, supporting the same conditions3Different samples were tested, meeting the standard requirements for parallel testing. On the basis of ensuring independent testing of the samples, the testing efficiency was improved3Twice. The internal temperature and humidity of the equipment are automatically adjusted, and temperature and humidity sensors are installed in each testing chamber to monitor the temperature and humidity situation, making the testing process more precise. The temperature control range is10℃~ 55℃The humidity control range is oxygen0%RHThe5%RH ~ 90%RH.The testing range for the oxygen permeability of thin films in this instrument is0.01～200 cm³/(m²·day)(standard)Alternatively, an optional packaging testing device can be used to complete oxygen permeability testing for container packaging products, with a testing range of0.00005～1 cm³/(pkg·d).

This instrument meets the requirementsASTM D3985TheASTM F1307TheASTM F1927(Optional)GB/T 19789TheGB/T 31354TheDIN 53380-3TheJIS K7126-2-BTheYBB 00082003-2015Multiple national and international standards can meet the oxygen permeability testing of containers made of plastic, rubber, paper, paper plastic composite, glass, metal and other materials under different temperature and humidity environments, such as yogurt cups, cola bottles, peanut oil barrels, vacuum packaging bags, metal three piece cans, plastic cosmetics packaging, toothpaste hoses, jelly cups, etc. And it can test the oxygen barrier properties of various plastic films and sheets.

2. Preparation of samples

Translate into English3A intact yogurt cup sample is placed in the laboratory23℃The50%RHConditioning state in the environment of48Hour.

3. Test conditions

Location: Jinan Languang Packaging Safety Testing Center

Test temperature and humidity:23℃，50%RH

Test method: isobaric method (i.e. Coulomb sensor method)

4. Test steps

4.1 Test principle

C230HBased on the Coulomb oxygen analysis sensor and the principle of isobaric testing, the pre processed sample is clamped between the testing chambers. Oxygen or air flows on one side of the membrane, and high-purity nitrogen flows on the other side of the membrane. Oxygen molecules diffuse through the membrane into the high-purity nitrogen on the other side, and are carried to the sensor by the flowing nitrogen. By analyzing the oxygen concentration measured by the sensor, the oxygen permeability and other results are calculated; For packaging, high-purity nitrogen flows inside the packaging, while air or oxygen surrounds the outside of the packaging.

4.2 Sample clamping

Seal the sample on the container sealing device with transparent quick fix adhesive; After sealing, clamp it inside the container testing device and tightly wrap the area above the tray of the container sealing device with a sealed bag. Install other components according to the above method2A sample.

4.3 Testing process

C230HAutomated testing, simple testing process:

l Add distilled water, turn on the system air source, and adjust the air source pressure as required. According to the experimental requirements, add an appropriate amount of distilled water to achieve the desired resultsO₂TheN₂Humidity.

l Turn on the power and run the software.

l Set the test temperature, test parameters, and start the test. The experimental parameters include control parameters (experimental mode, number of experimental cycles, experimental timeRESERVATIONNumber of cycles, etc.) and sample parameters (type, area, thickness, etc.).

l Adjust humidity and carrier gas flow rate during the experimental process.

l End of experiment and data processing.

l Turn off the gas source and power supply.

The average oxygen permeability of the three yogurt cup samples in this experiment is0.0571 cm³/(pkg·d).

Summary:

adoptLabthinkLan GuangC230HThe oxygen permeability testing system can obtain high-precision oxygen barrier results when testing the oxygen permeability of plastic yogurt cups, accurately reflecting the barrier performance of yogurt cups. The testing equipment and inspection standards used in this experiment are also applicable to oxygen permeability testing of containers with certain barrier properties for other purposes.LabthinkLanguang has always been committed to providing professional testing services and equipment for full (separated) ball customers. For many years, it has been dedicated toFull (separated) ballThe customer has provided tens of thousands of barrier testing services, providing reliable data support for the customer.Understand the relationshipFor more information on related testing instruments, you can log in to the website of Jinan Languang CompanyView specific information or callconsulting serviceLabthinkLan Guang looks forward to enhancing technical exchanges and cooperation with enterprises and institutions in the industry.