Packaging plays a very important role in preserving, protecting and preventing the food from getting spoiled. Faulty packaging can undo all the attempts of preserving the food made by the food processor during the manufacturing process. That is why, a food manufacturer must have appropriate knowledge about the different types and functions of packaging.There are a number of packaging techniques and materials available to suit the variant degree of food products in terms of their size, nature, bulk density, perishability e.t.c. Although packaging serves multiple purpose at the same time, but the most important purpose it should serve is – ‘Extending the shelf life of food’. One such technique of packaging that extends the shelf life of food by packaging the product (in a gas impermeable package) under a preservative gaseous environment is called Controlled Atmosphere Packaging (CAP).
Controlled Atmosphere Packaging (CAP) is a system whose objective is to extend the shelf life by altering the gaseous environment in and around the food product. It is specifically used for perishable foods like meat, poultry, fish, high-moisture pasta and fruits like apple, pears and some vegetables. CAP can also be termed as ‘Gas Flushing’. This is because a mixture of different gases is flushed or inserted in the package while replacing the air which extends the shelf life.
The fruits and vegetables consume Oxygen and give off Carbon dioxide during storage. There are three ways to slow down this respiration and other physiological changes. The first one is to reduce the temperature of surroundings; second, reducing but not eliminating Oxygen; third, increasing the amount of Carbon dioxide. Due to reduction in temperature, the biochemical reactions occurring due to various enzymes, are inhibited. Lowering the amount of Oxygen level leads to inhibition of the growth of spoilage causing microorganisms and increasing the Carbon dioxide level leads to the killing of microorganisms (e.g. molds which are aerobic). The optimum temperatures, relative humidities and gas compositions differ for different fruits and vegetables.
Role Of Gases in Controlled Atmosphere Packaging
In controlled atmosphere storage, the atmosphere is controlled by adjusting the levels of three particular gases – Oxygen, Carbon dioxide and Nitrogen, where each gas plays a specific role mentioned as below:
- Oxygen: Preserves the red colour of meat.
- Carbon dioxide: Prevent the development of molds and bacteria.
- Nitrogen: Being an inert gas, it prevents respiration and enzymatic activity.
Examples Of Controlled Atmosphere Packaging
In the case of meat, poultry and fish, the animal tissue consumes and gives off gases in the atmosphere and this gas equilibrium affect many food properties. Several examples of these properties include pigment changes of red meat, growth and metabolic patterns of surface ripening as well as spoilage microorganisms and the staling rate of cold storage eggs.
In meat, Carbon dioxide enters the animal tissue and produces acid carbonate. This result in lowering the pH of the meat and thus the development of spoilage microorganisms is retarded or completely inhibited. In the case of eggs, apart from oil or wax coating (also called surface coagulation of egg shell) to minimize the loss of water and carbon dioxide, eggs have been stored in warehouse enriched with Carbon dioxide to minimize loss of this gas which has an impact on the pH and freshness of egg.
Another type of CA storage is ‘Hypobaric Storage’. In this case, the storage area is maintained under reduced pressure and high humidity. Due to this, the amount of air is decreased and with it, the amount of Oxygen in the storage and high humidity prevents the dehydration of food product. Hypobaric storage has been used in warehouses as well as enclosed truck bodies.
CAP requires the use of strict control of quality and storage temperatures in order to ensure the safety and quality of food products. Lack in proper control can lead to detrimental effects on the quality of food. These changes are influences by a number of factors like growing conditions, feeding practices of animals, conditions of harvest or slaughter, sanitation and damage to tissues, temperature of cool storage, conditions while packaging the commodity, and other variables.
Advances in controlled atmosphere storage technology include faster establishment of desired atmosphere, less fluctuation in O2 and CO2 levels, ability to change atmospheric composition as needed during storage, and ability to scrub ethylene from the storage environment.
Advantages Of Controlled Atmosphere Packaging
- The storage life of various fruits and vegetables can be increased by 2 to 4 times the normal life by employing Controlled Atmosphere storage technology.
- Controlled atmosphere packages allow reaching markets that are geographically far from the point of packaging for sensitive materials.
Disadvantages Of Controlled Atmosphere Packaging
- CA stored produce deteriorate rapidly when exposed to normal atmospheres during marketing.
- The involvement of bulky and sophisticated equipment limits the use of CA technology during transport and retail storing of fruits and vegetables.
- Sophistication of packages and intense control of atmosphere leads to higher costs.
Controlled Atmosphere Packaging Video
- Food Science, 5th edition by Norman Potter and Joseph H. Hotchkiss.
- Food Packaging study material, prepared by Dr. S. Kaleemullah, Acharya N. G. Ranga Agricultural University.
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