Modified Atmosphere Testing (MAT)
Manufacturers of sensitive or perishable products want to guarantee first-class product quality over long periods of time. Modified atmosphere packaging preserves the freshness and quality of products and extends product shelflife for food producers.
This is why packaging under protective gas (MAP-Modified Atmosphere Packaging) has become firmly established, particularly in the food and luxury food industry. In addition to uncompromising hygiene, the highest demands are placed on the technical equipment for quality assurance.
Our high-quality gas analysers (MAT-Modified Atmosphere Testing) are used for monitoring protective gas packaging. These test the shielding gas mixtures of N2,CO2 and O2.
Inert gas Nitrogen (N2)
Nitrogen (N2) is present in approximately 78 % of air. It is an inert gas and does not react directly with the food. As a packaging gas, it is used in peculiar to suppress oxygen (O2) out of air. This indirectly prevents the oxidation of food and inhibits the growth of oxygen-dependent (aerobic) microorganisms.
Inert gas Carbon dioxide (CO2)
Carbon dioxide (CO2) is an important protective gas. It changes the pH value of the product environment and reduces the formation of mould or the growth of bacteria, because it influences the permeability of the cell membrane. The concentration must be chosen carefully, because when it is dosed too high, CO2 has a taste-altering effect. Furthermore, due to its high fat or water solubility and high permeation capacity, it can easily cause packaging to lose pressure.
Inert gas Oxygen (O2)
Oxygen (O2) is present in natural air at a concentration of about 21% and is a condition for the growth of aerobic microorganisms. O2 favours oxidation-induced spoilage. Therefore, in modified atmosphere packaging, oxygen is normally significantly reduced or even eliminated. For fresh red meat, on the other hand, the oxygen content will be increased to maintain or intensify the red colour.
How does modified atmosphere packaging (MAP) work?
Exchange of the ambient air in the packaging
Modified gas mixtures of nitrogen (N2), carbon dioxide (CO2) and oxygen (O2) are used for packaging under protective gases. These protective gases also exist as naturally occurring components in the air.
Inert gas packaging: Put simply, the natural ambient air in the packaging is replaced by a modified gas mixture. The concentration of the protective gases N2,CO2 and O2 is used in different mixing proportions depending on the requirements and product.
These modified gas mixtures are constantly monitored, either on the packaging line, in the laboratory or in the trade routes. Quality assurance is carried out using gas analysers.
Sensor technology of the gas analysers
Protective gas packaging is checked with gas analysers. These work with modern sensor technology and different sensor variants: Electrochemical oxygen cells (EC), non-dispersive infrared sensors(NDIR) or (ZrO2). All these sensors are precise and only require very small amounts of gas (approx. 3-7 ml).
The MAT1400 & MAT1500 models are equipped with a non-dispersive infrared sensor (NDIR) and zirconium dioxide sensor(ZrO2).
Function using the example of the ZrO2 sensor: A ZrO2 membrane heated to 750 °C separates the measured gas from the ambient air. Due to the Yttrium oxide stabilization of the membrane, oxygen ions diffuse towards the lower oxygen concentration. Both sides of the membrane are coated with a gas-permeable platinum film. Electrodes are used to measure the difference in electrical voltage between the two sides of the membrane. This is measured and the oxygen concentration of the measured gas is calculated from this.
Open slider and get to know how inert gas analysis work in practice
Typical applications for gas analysis
In the case of snacks, nuts, spices or coffee, the greatest risk of spoilage is the high fat content. Oxidation causes fats to go rancid quickly. To inhibit this, the oxygen in the packaging is greatly reduced and replaced by a pure nitrogen atmosphere (N2). The very economical MAT1100 gas analyser is perfect for testing this special protective atmosphere.
To lengthen the shelf life of milk powder, especially highly sensitive baby food products, it is important to displace oxygen from the packaging. In practice, baby milk powder is often packaged under pure nitrogen, with as little residual oxygen as possible. The quality assurance department is using the MAT 1400 gas analyser for testing.
Inert gas packaging as an important aspect of environmental sustainability
Especially in the case of fresh food, such as perishable organic meat, the sustainability aspect comes centre stage. These high-quality foods can be kept twice or three times as long under modified atmosphere packaging without losing any of their quality. Waste and food waste is avoided, packaging material is reduced.
The MAT1500 gas analyser is commonly used for checks in this sector of the food industry. One of the most important protective gas applications is fresh meat packaging (70-80% oxygen and 20-30% carbon dioxide). The device has a zirconium dioxide sensor (O2 measurement) and a non-dispersive infrared sensor (CO2 measurement).
Calibration and adjustment
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More InformationThe use of certified test gases
Analytical measurement results must be traceable. Traceability means the reproducible and complete control of measurement results through comparative measurements with a recognised standard.
This is done with our gas analysers using reference materials such as test and calibration gas mixtures of high quality. This allows to ensure that your analyser is operating without any deviation from the standard, either at self-defined intervals or on a daily basis.
You can also use our maintenance service for the technical inspection of components, adjustment of gas analysers with subsequent audit-proof calibration. This gives you the guarantee that your device will continue to deliver measurement results over a long period of use, with documented traceability and in accordance with recognized standards.
Gas mixtures and measured values
Each application has individual shielding gas mixtures
Gas analysers work quickly and provide reliable measurement results. They can also be easily integrated into existing operating processes.
In addition to the food industry, gas analysers are also used in quality assurance in the electronics, pharmaceutical and cosmetics industries.
Each industry works with different mixtures for the respective protective gas. Depending on the application, there are different concentrations in use.
For example, pure nitrogen gassing or equilibrium modified atmospheres (EMA) are applied for packaged fruit and vegetables in pre-cut form. The following is an overview of possible gas mixtures in various industries.
Typical areas of application
Gas analysers – indispensable devices in modern packaging processes
This is where gas analysers are used in practice:
- Sample measurements on the line during the packaging process
- Testing after revision: changes to the film or packaging materials
- Changes to the packaging machine: sealing seams, welding seams
- Retained samples, quality assurance in the laboratory
- Tests on the delivery
Below is a complete overview of sectors and industries that use gas analysis. You will also find out which MAT model is suitable for different applications.
Sensor technology of the device models
At the heart of the gas analysers is the sensor technology
Various models with different sensor technology are optionally available for optimum adaptation to the respective application. The respective proven sensor technology should be selected for each specific application and process. The range of sensors available allows optimum adaptation in terms of measurement range and accuracy:
- Electrochemical oxygen cell (EC)
- Zirconium dioxide cell (ZrO2) for O2 measurement
- Non-dispersive infrared sensor (NDIR) forCO2 measurement
The following overview provides an initial overview. We will be happy to discuss which device models are suitable for your specific requirements in a personal consultation.
Please feel free to contact us.
| Specification | MAT1100 device | MAT1200 device | MAT 1400 device | MAT1500 device |
|---|---|---|---|---|
| Application | Sporadic O2-sample check | Combined O2- and CO2-measurement | High sample throughput High O2-concentration | High sample throughput High O2-concentration + Combined O2- and CO2-measurement |
| Advantage model version | Cost-effective option, fast operational readiness, low drift | Cost-effective option, low drift, environmentally compensated CO2 measurement | Long lifespan, fast measurement, high precision measuring lowest O2-concentrations, wide measurement range, drift-free | Long lifespan, fast measurement, high precision measuring lowest O2-concentrations, wide measurement range, ZrO2: drift-free, NDIR: drift-free, environmentally compensated CO2 measurement |
| O2 sensor technology | Electrochemical oxygen cell (EC) | Electrochemical oxygen cell (EC) | Zirconium dioxide sensor (ZrO2) | Zirconium dioxide sensor (ZrO2) |
| CO2 sensor technology | Non-dispersive infrared sensor (NIR) | Nichtdispersive Infrarotsensor (NIR) | Non-dispersive infrared sensor (NIR) | Non-dispersive infrared sensor (NIR) |
| N2 sensor technology | Arithmetic determination | Arithmetic determination | Arithmetic determination | Arithmetic determination |
How to Use
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