What Is Headspace Analysis?

Headspace is the term used within the food industry to refer to the residual air within a sealed packet. The air that remains in the packet is sometimes normal air. Other times, a mix of gases is used instead of air to extend the shelf life of food.

Typical headspace gases include nitrogen (N2), carbon dioxide (CO2), or carbon monoxide (CO2). 

Headspace analysis is the technical test to determine gas levels within the food packaging. Performing this test accomplishes the following:

• Ensures the food packaging production line is operating as expected.
• Provides a quantitative quality control key figure.
• Ensures the packaging is not compromised with pinholes or poor adhesion.

Most popular Headspace Oxygen Analyzer?

Of all the different types of gas to be detector by a headspace analyzer, the most popular in terms of sales volume is the Headspace Oxygen Analyzer.

What Is Modified Atmosphere Packaging (MAP)?

When air is replaced with a gas mixture (i.e CO2, N2, or CO) during food packaging, this process is called modified atmosphere packaging (MAP).

MAP technology extends shelf life by reducing the oxidation and spoilage of perishable food and beverage products. 

MAP is commonly used in a variety of foods, both produce, and dry products. Broccoli, sausage, nuts, and coffee are only a few examples of packaged foods that utilize this technique.

Why Do Foods Require MAP?

In most food packaging applications, an important objective is to extend shelf life. This can be accomplished by introducing a unique gas or gas mixture into the food packaging to reduce:

• Oxygen and rate of oxidization.
• Growth of bacteria or mold.
• Food degradation by reducing lipolysis.
• Breakdown of food proteins.
• Other physicochemical deterioration processes.

Extending shelf life also limits food waste, enables retailer versatility, and ultimately improves the freshness of food over an extended period of time. All in all, extending shelf life provides better value for the end customer.

What Is a Headspace Analyzer?

Headspace analyzers are sometimes called MAP analyzers or food packaging analyzers. The device has a built-in pump that withdraws a gas sample from a packaged food product using a small probe or syringe.

From there, the gas is passed to sensors that reside within the analyzer. The voltage changes based on the gas concentration and sensor output. Based on curve fitting algorithms, the analyzer determines the concentration of gas.

The most common headspace analyzer is an oxygen headspace analyzer. In most cases, food packets undergo a nitrogen flush to remove as much oxygen as possible. Analyzing oxygen concentration is very important and one of the most common headspace analyzer tests.

What Is a MAP Analyzer?

A MAP analyzer is also known as a modified atmosphere packaging analyzer. It is synonymous for a headspace analyzer and is also called a food packaging analyzer. Don’t get confused, these terms all refer to the same piece of equipment.

Which Gases Are Used for MAP and Headspace?

The typical gases used for headspace include carbon dioxide (CO2), nitrogen (N2), and carbon monoxide (CO). Depending on the food and packaging type, the types of gases and their ratios will vary. These differences will affect the physicochemical deterioration, such as oxidation, lipolysis, and proteolysis.

Examples of packaged foods and typical MAP gas compositions include:

• Fresh fruit and vegetables 

• Gas mix of 90% N2, 5% O2, and 5% CO2

• Cheese

• Cottage cheese = 100% CO2
• Provolone = 30% CO2 and 70% N2

• Meat

• Cooked meat, such as burger patties = 70% N2 and 30% CO2
• Raw meat, such as beef and pork = 70% O2 and 30% CO2

• Dried food

• Coffee and nuts: 100% N2

How Do I Perform a Headspace Analysis?

Performing a headspace analysis is straightforward. The test process goes something like this:

1. Ensure you have your needle, filter, and tubing attached to the MAP analyzer.
2. Ensure the analyzer pump is operational.
3. Ensure the analyzer is calibrated. If detecting oxygen, ensure the O2 is reading 20.9%, CO2 is reading <0.1%, and CO is reading 0%.
4. Place a septum on the food packaging. 
5. Place the needle through the septa and into the package. Turn the pump ON and take a gas sample
6. As the sample is taken, the packaging will shrink since gas is being drawn out of it.
7. Take note of the gas concentration on the analyzer. Once the levels have stabilized, record the data.

An example of headspace analysis is shown below using coffee packaging.

What Are the Best Headspace Analyzers?

• Forensics Detectors Headspace MAP Analyzers
• Systech Illinois MAP Analyzers
• Mocon Headspace MAP Analyzers
• Novatech Food Packaging Analyzers
• Quantek Instruments Food Package Testing
• Bridge Analyzers MAP Analyzers
• AGC MAP Analyzers

What Are the Most Important Headspace Analyzer Considerations?

Gas Target

Trivial yet important. Define exactly which gases you wish to measure. Is it a single gas such as O2 or dual gases such as O2 and CO2?

Detection Range and Resolution

You also want to make sure you purchase an analyzer with the correct detection range and resolution. For example, when detecting O2, are you targeting residual O2 or the high amounts required for meat products? For residual oxygen, you need to ensure complete zero oxygen using a gas analyzer with 0.01% (100 ppm) resolution.

Size and Mobility

Traditionally, headspace analyzers have been built as desktop instruments. With the creation of faster and smaller electronic components, handheld versions are available.

Accessory Options

This is an important factor as it adds to the ongoing costs. Check if any proprietary accessories such as filters, septas, or needles are required that may add to your operational costs. In some cases, generic components can be substituted to reduce ongoing costs.

Calibration

Understand the calibration requirements of your analyzer. If it requires shipment and third party calibration, this will result in increased operational costs.

Sensor Lifetime

Ensure you understand sensor lifetime and replacement options as all sensors have a finite lifetime.

What Are Headspace Analyzer Accessories?

A headspace analyzer requires accessories to perform a headspace analysis. 

Needles

Needles come in all different shapes and sizes. Ensure your needle can be purchased in different gauges, in case your application requires something unique. Ensure the needle is not blocked by debris from food, packaging, or the septa.

Filters

A filter is important to protect your analyzer from any food particles or packaging debris that may be sucked in during MAP analysis. 

Septa

These are your most high-volume consumables. The septa is a rubber or foam pad that is used to ensure a tight fit when the needle penetrates the packaging. This guarantees that no air gets into the package and no gases inadvertently escape.

Tubing

Ensure your tubing is as short as possible for faster headspace analysis. Check that the tubing is food grade and has good flexibility, such as food-grade silicone tubing.

 

Why Are Headspace Analyzers So Expensive?

Headspace analyzers are expensive because they include expensive components. The hardware consists of a computer with a power microprocessor to analyze the sensor information and translate outputs into meaningful concentration values. Most of the cost is from the actual gas sensor, which changes electronic output signal based on the gas concentration detected.

Do Headspace Analyzers Require Calibration?

Yes they do. All headspace analyzers require periodic calibration. At Forensics Detectors, we recommend calibrating every 6 to 12 months.

Headspace analyzer calibration is a technical procedure performed every 6 to 12 months to ensure your gas detector is functioning accurately. Over time, gas detectors and their respective sensors degrade, some faster than others. The only way to ensure accurate readings is via gas calibration.

Gas calibration involves exposing your gas analyzer to a traceable concentration of test gas. Doing so in a controlled environment and using certified gas from the National Institute of Standards and Technology (NIST) adjusts the calibration curve of your gas detector to report accurate results.

What do customers think?

You will be surprised to know that very large supermarket and food companies use the Forensics Detectors headspace analyzer. They are easy to use, cost-effective and are fully controllable. In addition, all the accessories are standard items that can be purchased from any vendor. Below is a small business using our headspace analysis for sandwich production.

 

 

Final Words

A headspace analyzer is an important instrument for companies that manufacture and package various foods. As an analytical tool with sensitive sensors, headspace analyzers require some care and maintenance. A headspace analyzer provides food packers with quantitative gas concentrations so that products meet the expected quality control thresholds.