In the MAP process, there are different systems that have been developed for different food requirements.
Vacuum packaging involves the removal of air, particularly oxygen, to create a vacuum to prevent oxidation. Oxidation refers to chemical reactions that occur in the presence of oxygen, for example, when a sliced apple oxidises and becomes brown in colour. Oxidation also leads to the development of ‘off ‘ flavours and odours, known as rancidity. Appropriate types of food are stored in a vacuum environment, usually in an airtight bag or bottle. The vacuum environment removes atmospheric oxygen and any free moisture and forms a tight fit around the food, inhibiting bacterial or fungal growth and thus preventing food spoilage.
Examples of foods using this system are cheeses, salami, ham and fresh noodles.
Fig (a): An example of how foods are vacuum packaged
Gas packaging replaces the air in a package with a carefully selected mix of gases before it is sealed. The atmosphere inside individual packages can be altered by adjusting the levels of oxygen and carbon dioxide. In this way, spoilage and ripening can be controlled and mold growth can be reduced. Many food plants produce ethylene as part of their normal metabolic cycle. Ethylene is a simple organic compound, which triggers ripening and ageing, which explains why fruits such as avocados and bananas ripen quickly when kept in the presence of ripe or damaged fruits in a container, and why vegetables such as broccoli turn yellow even
when kept in a refrigerator.
Examples of foods using this system are fruits and vegetables, fresh meat, potato chips and refrigerated pastas.
Fig (b): Gas packaging replaces the air in a package with a carefully selected mix of gases before it is sealed
Advantages of MAP Packaging
The advantages of MAP packaging include:
- MAP packages increase the shelf life of meat from 3 to 21 days, cheese from 7 to 180 days, and fresh pasta from 3 to 60 days.
- For food producers, shelf life extension often lowers the cost of a product by reducing spoilage, as well as providing long-distance export options.
- For growers and consumers, it can extend the seasons of certain fruits and vegetables.
- Because MAP packaging enables processors to extend shelf life without using chemicals, it is also ideal for the packaging of organic produce.
Fig(c): Ways in which gas packaging prevents spoilage in MAP packaging for fruit and vegetables
That is why prefer the MAP packaging over the other packaging like aseptic packaging.
Syed Mudabbar Hussain Shah
The Author is final year student of
B.Sc (Hons.) in Food Engineering
Department of Food Engineering
University of Agriculture, Faisalabad