Linde LienHwa Group

Food manufacturers are always looking for ways to extend shelf life without altering the physical or chemical properties of foodstuffs or adding any unnatural ingredients. Modified Atmosphere Packaging (MAP) is the ideal way to achieve this. It is a natural method that is rapidly growing in popularity worldwide. In many cases, it can also complement alternative preservation methods.

We have developed a range of application-specific packaging solutions under our MAPAX^® brand. Synergizing the vast knowledge we have gained in food science, gas mixtures and packaging, MAPAX extends shelf life – the natural way.

With MAPAX, you can:

Success Through Partnership

We work closely with food research institutes in many countries and have numerous food-processing customers worldwide. We also collaborate closely with the suppliers of packaging materials and machines to create the best atmosphere for each individual application. This is influenced by a number of factors, including the foodstuff and its properties, microbial activity, hygiene requirements, pre-packaging delay, temperature, permeability and other properties of the packaging material, the free gas volume within the package and the residual oxygen level.

So, for instance, in the case of low fat products with a high moisture content, MAP focuses on inhibiting the growth of microorganisms in particular. However, in the case of products with a high fat content and low water activity, oxidation protection is the primary objective.

The Technology

MAPAX gas mixtures usually consist of the normal atmospheric gases such as carbon dioxide (CO₂), nitrogen (N₂) and oxygen (O₂). Microbial growth can also be inhibited to a certain extent with the help of other gases such as nitrous oxide (N₂O), argon (Ar) and hydrogen (H₂). These gases can be applied individually or mixed according to specific ratios.

CO2, for instance, is most effective in inhibiting microorganisms (such as mould and other common aerobic bacteria). It does this by dissolving into the food’s liquid and fat phase, thereby reducing its pH value. It also penetrates biological membranes, causing changes in permeability and function. As an inert gas, nitrogen is primarily used to replace oxygen in packaging, thereby preventing oxidation. Owing to its low solubility in water, nitrogen also helps to prevent package collapse by maintaining internal volume.

Although the oxygen level should be as low as possible in most food packages, meat is an exception. Here oxygen helps to preserve the oxygenated form of myoglobin, which gives meat its red color. It is also valuable for fruit and vegetables as it lets them breathe.