Modified Atmosphere Packaging (MAP) refers to technologies used to control the atmosphere inside packaging of perishable foods. The most common objectives are to extend shelf life, maintain product quality, or enable controlled ripening processes. This can involve completely substituting the air inside the package with a less reactive gas or creating a controlled ventilation system within the packaging.
Modified Atmosphere Packaging encompasses a broad array of applications and technologies. In this chapter, we will delve into some key distinctions and explanations of these technologies.
In the world of food packaging, maintaining product quality while extending shelf life is of the utmost importance. In MAP Packaging two methods often employed are Breathable Packaging and Air-Substitution, each with its unique approach and benefits.
Breathable Packaging is designed to regulate the exchange of gases (like oxygen and carbon dioxide) between the packaged product and its external environment.
This is primarily achieved through microperforations in the packaging material, which are often laser-created. This method is particularly beneficial for products that emit gases as they ripen, such as fruits and vegetables.
By allowing these gases to escape and fresh air to enter, breathable packaging helps in controlling the ripening process and preventing spoilage. It's ideal for products that require a certain level of moisture and air exchange to maintain freshness.
On the other hand, Air-Substitution, also known as gas flushing, involves replacing the air inside the packaging with a specific gas or mixture of gases, typically nitrogen or carbon dioxide.
By removing oxygen, which accelerates spoilage and degradation, and replacing it with a less reactive gas, air-substitution significantly extends the shelf life of perishable goods.
This technique is especially useful for products that are sensitive to oxygen, including meat, dairy products, and some prepared foods. It helps in preserving taste, texture, and nutritional value over a longer period.
While Air Substitution is often used when vacuum packaging is not possible there is also a combination of both called “Active Vacuum”.
When it comes to breathable packages, there are two main options to consider: Barrier Packaging Films and Porous Films. Each type has its own set of characteristics and applications, making them suitable for different packaging needs.
Barrier Packaging Films are specialty films with a decreased permeability to gases, like oxygen and moisture, thereby preserving the quality and extending the shelf life of the product.
They are usually made of low-density polyethylene (LDPE), aluminium foil (AL), or polypropylene (PP) and consist of multiple layers to allow for a certain degree of permeability.
Their main advantage is the protection against intrusion of moisture, liquids or insects into the packaging. However this comes with a significantly higher price while often the same atmospheric requirements can also be achieved with porous films.
Porous films are, simply put, “normal” films with a micro- or macroperforation. Therefore they are significantly cheaper than Barrier Packaging Films.
Porosity is usually achieved by laser perforation, which is a highly flexible production method. Thus many different characteristics and degrees of breathability can be achieved with mere software changes.
In some cases, especially many fruits and vegetables there is no alternative to porous films as the required degree of gas exchange cannot be achieved with special films.
Fruits and vegetables, which emit gases like ethylene, benefit greatly from MAP. By adjusting the levels of gas exchange, MAP slows down the ripening process, reduces spoilage, and retains freshness.
MAP is vital in preserving the texture and freshness of bakery items. By controlling the oxygen and moisture levels, it prevents the growth of mold and bacteria and reduces staling.
Breathable Packaging extends the life of cut flowers and potted plants. By controlling the ethylene gas within the packaging, MAP slows down the aging and wilting process.
For meals that are packaged hot, Modified Atmosphere Packaging is essential to prevent spoilage and maintain quality. By allowing the escape of steam and controlling the internal atmosphere, MAP ensures that meals retain their desired texture and taste.
MAP is particularly crucial in preserving the color, texture, and freshness of meat, poultry, and seafood. By reducing the oxygen level, it inhibits the growth of aerobic bacteria and prolongs shelf life.
Cheese, yoghurt, and other dairy products are sensitive to microbial growth and oxidation. MAP helps in extending their shelf life by creating an optimal gaseous environment.
Snack foods and processed items require protection from moisture and air to maintain crispness and prevent spoilage. MAP helps in preserving the quality and extending the shelf life of these products.
In beverages like coffee and tea, MAP plays a role in preserving flavor and aroma by preventing oxidation.
MAP technology is also employed in microwaveable packaging to allow steam to escape during cooking. This prevents pressure build-up and ensures even cooking of the food. Additionally, laser scribing techniques can be used to create specific contours for effective steam venting.
MLT offers solutions to create porous films during the converting process as well as inline machines that can be directly integrated in the packaging process. Our laser technology facilitates a combination of processes such as perforating, scoring, and laser cutting, all in one streamlined operation.
Our expertise lies in the high-speed laser processing of moving materials. We pride ourselves on our exceptional flexibility, tailoring solutions to meet the unique needs of your production process. Our commitment extends to global integration and service support, ensuring your operations run smoothly and efficiently.
Thus the use of conventional films with perforation is usually cheaper than the use of special porous films.
There are scenarios where the use of non-porous films is necessary. These films provide a controlled barrier against environmental factors and effectively block the entry of liquids, dirt, and small insects. The barrier properties of non-porous films make them suitable for applications where protection from external contamination is crucial.
Nitrogen (N2):
Nitrogen is an inert gas and is primarily used for its non-reactive properties. It does not react with foods and thus, helps in preventing oxidation and spoilage. Nitrogen is often used to displace oxygen in the packaging, reducing the rate of aerobic microbial growth and oxidation.
Carbon Dioxide (CO2):
Carbon dioxide is effective in inhibiting the growth of bacteria and mold. It is often used in packaging of products like meat, poultry, and cheese. However, high concentrations of CO2 can dissolve in fats and water, leading to product quality changes, so its levels need to be carefully controlled.
Oxygen (O2):
While oxygen is generally removed to prevent spoilage and oxidation, it is sometimes used in controlled amounts in MAP.
