The Process
In the MAP process, there are different systems that have been developed for different food requirements.
Vacuum Packaging
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.
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.
Oxidation results in browning and development of 'off' flavours and odours, known as rancidity.
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Common foods that are vacuum packaged include cheeses, salami, ham, fish and fresh noodles.
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Gas Packaging
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.
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.
Gas packaging replaces the air in a package with a carefully selected mix of gases before it is sealed
Foods that are commonly gas packaged are fruits and vegetables, fresh meat, potato chips and refrigerated pastas
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Active Packaging (also known as Barrier-Specific Packaging)
Active packaging addresses the issue that fresh food is still biologically active inside a package, and therefore still releases water and gases. With increases in humidity in the package, microbial activity occurs. In addition, ripening of the food is encouraged by the ethylene produced by the food, oxygen is used up and carbon dioxide content rises, encouraging spoilage.
Unless oxygen is excluded, it can cause the development of an 'off ' flavour, colour change or nutrient loss in a food product, as well as increase its susceptibility to microbial attack.
For this reason, active packaging is used to control and react to the environment surrounding the food product inside the package. Active packaging often incorporates features that block the transfer of substances such as moisture, oxygen and ultraviolet light; this type of packaging is said to have 'barrier properties', and it gives foods an extended shelf life.
Active packaging technologies include materials that absorb self-life-reducing gases such as oxygen or ethylene in fruit. Active packaging incorporates additives into the packaging film or within the package containers, which in turn maintains food quality and extends product shelf life, through inhibition of browning, inhibition of dehydration and control of chilling injury.
Examples of active packaging include:
- oxygen scavengers - to prevent oxidation, 'off' flavour development, colour change or nutrient loss. E.g. sachets in meat trays
- ethylene scavengers - to suppress produce respiration and reduce rotting
- moisture absorbers - to prevent staling
- flavour/odour absorbers - to remove to remove undesirable flavours and odours
- edible films and coatings - to optimise shelf life, provide higher margins, offer product novelty and improve convenience and food safety
High barrier film and foil packaging
Active packaging sachets or films can be used to scavenge oxygen or ethylene, or absorb moisture, flavours and odours, depending on its purpose and the food item
Light-activated oxygen scavenging films by Cryovac® OS Films
A new and emerging innovative active packaging system are the edible films and coatings, which optimise shelf life, provide higher margins, offer product novelty and improve convenience and food safety
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