Headspace Gas Analysis and Quality Control-Labthink i-GASATEK 6900 Headspace Gas Analyzer

Oxygen and water vapor are the main factors that influence the shelf life of products. Research indicates that the shelf life could be extended and the product quality could be guaranteed in storage by controlling the headspace of the package. Therefore the film with excellent barrier property has found its application which boosts the development of this industry. It should be noted that for MAP, CAP and other gas-filled packages, the gas used to fill the package hardly contains oxygen. If the gas escapes from the package, the content of oxygen will be raised. Moreover, a small amount of air would remain in the package in gas filling process. As a result, the actual gas composition inside the package may be a little different from expected. What problems will be brought about if the proportion of oxygen contained in gas-filled package rises? How to solve those problems? This article is to introduce the headspace gas analysis and the quality control of finished package as well some suggestions would be given for purchasing headspace gas analyzers.

1 Why perform headspace gas analysis

It is certain that gas exist in packages of flavor snacks, baked food, meat products, dairy products, coffee, juice, carbonated drinks, tablets, oral liquid, perfume and toiletries etc. Even for the so-called “Vacuum package”, through the gas content is reduced to a minimum level, there is still a little remaining gas inside the package. Gas can not be completely ruled out.

It is very difficult to control or change the gas composition in the package by technical means since the product filling is finished until the package is opened. Application of packaging materials with barrier property could prevent the gas permeate through the package only. The remaining oxygen and other gases inside the package could not be expelled yet (if deoxidizer is used, the oxygen could be reduced). Therefore, if oxygen or other product-sensitive gases exist inside the package, the product quality would be affected as well the gas composition would be changed gradually. In order to minimize the content of specific gases, MAP and CAP packages are widely used. The inert gas is critical to extend shelf life of products. Generally carbon dioxide and nitrogen are used in package. However, when the product has been stored for a long period, the gas composition would be changed gradually. No matter what the form of package is, it is difficult to get the correct gas composition inside the package. As a result, it becomes difficult to analyze the product quality, estimate the shelf life and design the package accordingly. Actually headspace gas analysis is to test the gas composition at the top of the package which would be the solution to the above problem. Headspace gas analysis has become a major means by which the package quality could be examined and the shelf life of product could be verified.

2 Test Items of Headspace Gas Analysis

The main target of headspace gas analysis is Oxygen and carbon dioxide.

Oxygen could destroy the nutrient of food as well it would cause oxidation of grease contained in food and that is why the food goes smelly or become toxic. Additionally oxygen is necessary for the reproduction of bacteria (bacteria reproduction is the main reason for food deterioration). When the percentage of oxygen content is less than 2% and carbon dioxide content is more than 7%, food and bacteria are in a state of “hibernation”, so the shelf life of food could be extended effectively.

Many pharmaceuticals, such as low-priced iron salt, iodide, nitrite and organic medicine with unsaturated carbon chains could be oxidized gradually when they are exposed to the air. Oxidation would change the appearance (color change) of pharmaceuticals. The pharmaceuticals may become ineffective even toxic because of decomposition caused by oxidation. Grease is also contained in cosmetics so deterioration (rancidity) of cosmetics could be also caused by oxidation.

Carbon dioxide gas is an important gas composition inside CAP package and MAP package. Its content is closely related to the shelf life of product especially for some carbonated drinks, it would directly influence the quality and flavor of the products. For the package of pharmaceuticals, content of carbon dioxide should be paid more attention to especially when some pharmaceuticals could interact with the carbon dioxide and become ineffective. For examples, some pharmaceuticals which contain hydroxide, oxide or calcium may absorb carbon dioxide and produce carbonates.

3 Suggestions for Purchasing Headspace Gas Analyzers

At present there are various types of headspace gas analyzers on the market. Here are some suggestions on how to select a suitable and reliable instrument.

1. The type of test gas. All of the headspace gas analyzers on the market could analyze oxygen content, but not all of them could be used to analyze carbon dioxide content. By analyzing the oxygen content, current product quality can be analyzed but it is not possible determine the reservation quality within shelf life of the product. Therefore, the headspace gas analyzer should be applicable in testing of multiple types of gases to ensure the accuracy of estimation of shelf life through the headspace gas analysis.

2. Volume of test gas. With the development of the packaging industry, small size package has become the trend. Accordingly the volume of the gas inside the package is decreased. However if the test gas collected by the detection probe is insufficient, the test would be unable to perform. Moreover the internal volume of the pipe connected with the detection probe should also be calculated. Generally the traditional handheld headspace gas analyzer requires a large amount of test gas which is the main disadvantage. Bench-top instrument could solve this problem by direct sampling.

3. System respond time. All of the headspace gas analyzers collect test gas with the same method that is to penetrate the seal area with probe. Actually when the probe penetrates through the package, there would be leakage around the penetrated area. The leakage would cause contamination to the test gas inside the package. Therefore the system respond time will influence the test result to some degree.

4. Lifespan of the sensor. Generally, the sensor equipped with the headspace gas analyzer is consumable part which is always surrounded by test gas. The lifespan of the sensor could not be extended. When it is consumed out, it should be replaced with a new one. Therefore the operator should pay attention to the lifespan of the sensor when selecting headspace gas analyzers.

5. Portability of the equipment and the convenience of data transfer. In order to analyze the actual quality of the product, it is possible that test process is not completed in the laboratory. Thus the instrument should be portable which is convenient for the operator to carry and operate in warehouse, shopping mall or in process of transportation even before the product is used. At present, most of the headspace gas analyzers could not print the results immediately after the test is finished. Although the test results could be stored in the instrument, it may cause confusion if a large amount of specimens need to be tested.

4 Advantages of Labthink i-GASATEK 6900 Headspace Gas Analyzer

i-GASATEK 6900 is the latest headspace gas analyzer(http://www.labthinkinternational.com/product/i-gasatek-6900-package-headspace-analyzer.html) developed by Labthink which combines the advantages of portable and bench-top instruments. 

First, both oxygen and carbon dioxide could be tested by this instrument with high precision.

Second, automatic sampling and manual sampling are available. Oxygen and carbon dioxide could be tested simultaneously. Minimum volume of test gas is required by manual sampling method so that the headspace gas analysis of small size package could be performed.

Third, special sampling needle, seal gasket and filter are equipped with the instrument. As well, the gas collection time and respond time are improved so that the accuracy and reliability of the test data could be guaranteed.

Fourth, the sensor equipped with the instrument is featured with long life span which could be used for at least 6 years under normal condition.

Fifth, although i-GASATEK 6900 headspace gas analyzer(http://www.labthinkinternational.com/product/i-gasatek-6900-package-headspace-analyzer.html) is larger than other portable instruments, it has exclusive printing function.

Additionally professional and portable tool box is equipped with this instrument which enables fast tests under various conditions.

5 Conclusion

Through headspace gas analysis, we could get the gas composition inside the package conveniently, quickly and precisely which could provide data support for analysis of product quality, shelf life and package design. Headspace gas analysis is necessary for quality control of the products.

Detailed information, pls contact Emily Wu via sales@labthinkinternational.com or visit our website: http://www.labthinkinternational.com/.

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