To study about different types of packaging.
Packaging can be defined as;” Techno-economic” function arrived at minimizing the cost of delivery while maximizing sales. It is a coordinated system of packaging goods for transport, distribution, storage, retailing, and use. Packaging plays a vital role in conservation, preservation, and transport.
Importance of packaging:
- Food packaging is an integral part of food processing and it is a link between food processors and consumers.
- Packaging protects the contents against dehydration, oxidation, light, flavour loss, environmental factors, and mechanical damage. It serves as a processing aid.
- The package is a convenient item for the consumer, can also be the cost-saving device.
- The package provides handling facilities for loading, transport, storage for long for both the processor and consumer.
Methods of packaging / Packing:
(1)Edible film packaging: An edible film or coating is simply defined as a thin continuous layer of edible material formed on, placed on, or between the foods or food components. The package is an integral part of the food, which can be eaten as a part of the whole food product. The selection of material for use in edible packaging is based on its properties to act as a barrier to moisture and gases, mechanical strength, physical properties, and resistance to microbial growth. The types of materials used for edible packaging include lipids, proteins, and polysaccharides, or a combination of any two or all of these.
The most common form of coating fruits and vegetables is a wax coating to retard respiration, dehydration, and senescence. Edible films selected should meet the requirements such as physicochemical and microbial stability, good sensory qualities, high carrier and mechanical efficiencies, free of toxic and safe for health, simple technology, non-polluting, and low cost of material and process.
(2) Modified humid packaging: Mostly used for highly perishable commodities like green leafy vegetables. MHP systems are designed to control not only dehydration but also condensation. Water absorbents like CaCl2, Sorbitol, or xylitol in the package or by use of packaging with good permeability enables to provide required MHP system.
(3) Protect packaging: The term is used to packaging which is primarily designed to protect the product than for appearance or presentation so, generally is used to the outer containers used for transporting goods from the manufacturer to the point of sale and filling materials inside the outer container, e.g, nylon barrier sealed bubble packaging.
(4) Shrinkwrap/Individual seal packaging: Individual seal packaging involves the use of heat shrinkable film (usually HDPE) that is wrapped around the individual units of fruits and vegetables and shrunk by blowing hot air over the package. Advantages of this packaging are ripening is delayed by the micro atmosphere created around the product. The films act an as a good barrier to water. Prevents the spread of disease from one product to another, improves the handling and sanitation of the product, and facilitates pricing and labeling of individual products. However, off odours may occur as the result of poor gas exchange and high RH.
(5) Active packaging: Another way of modifying the atmosphere pack is by using, “Active packing”. Packaging is termed as “Active” when it performs some desired role other than to provide an inert barrier to the external environment. The goal of developing such packaging is to create a more ideal match of the properties of the package to the requirements of the food. A wide variety of materials have been used for this purpose. Active packaging can be created by using oxygen scavengers, carbon- dioxide absorbents/emitters, ethanol emitters, and ethylene absorbents. The appropriate absorbent material is placed alongside the fresh produce. It modifies the headspace in the package and thereby contributes to the extension of the shelf life of the fresh produce.
(6) Vacuum Packaging: Vacuum packaging offers an extensive barrier against corrosion, oxidation, moisture, drying out, dirt, the attraction of dust by electric charge, ultraviolet rays and mechanical damages, fungus growth, or perishability, etc. This technology has commendable relevance for tropical countries with high atmospheric humidity.
In vacuum packaging, the product to be packed is put in a vacuum bag (made of special, hermetic fills) that is then evacuated in a vacuum chamber and then sealed hermetically in order to provide a total barrier against air and moisture. If some of the products cannot bear the atmospheric pressure due to a vacuum inside the package, then the packages are flushed with inert gases like Nitrogen and CO2 after evacuation.
Vacuum packaging offers an extensive barrier against corrosion, oxidation, moisture drying out, dirt, the attraction of dust by electric charge, ultraviolet rays and mechanical damages, fungus growth or perishability, etc. Vacuum packaging prevents freezer burn by preventing the food from exposure to cold, dry air.
(7) Controlled and Modified Atmospheric Packaging (CAP and MAP)- The normal composition of air is 78% Nitrogen, 21% Oxygen, 0.03% Carbon dioxide, and traces of other noble gases. Modified atmosphere packaging is the method for extending the shelf-life of perishable and semi-perishable food products by altering the relative proportions of atmospheric gases that surround the produce. Although the terms Controlled Atmosphere (CA) and Modified Atmosphere (MA) are often used interchangeably a precise difference exists between these two terms.
(8) Controlled Atmosphere Packaging (CAP)– This refers to a storage atmosphere that is different from the normal atmosphere in its composition, wherein the component gases are precisely adjusted to specific concentrations and maintained throughout the storage and distribution of the perishable foods. A controlled atmosphere relies on the continuous measurement of the composition of the storage atmosphere and injection of the appropriate gases or gas mixtures into it, if and when needed. Hence, the system requires sophisticated instruments to monitor the gas levels and is therefore practical only for refrigerated bulk storage or shipment of commodities in large containers. If the composition of the atmosphere in the CA system is not closely controlled or if the storage atmosphere is accidentally modified, the potential benefits can turn into an actual disaster. The degree of susceptibility to injury and the specific symptoms vary, not only between cultivars but even between growing areas for the same cultivars and between years for a given location. With tomatoes, excessively low O2 or high CO2 prevents proper ripening even after removal of the fruit to air, and CA enhances the danger of chilling injury.
(9) Modified Atmospheric Packaging (MAP)—Unlike CAPs, there is no means to control precisely the atmospheric components at a specific concentration in MAP once a package has been hermetically sealed. Modified atmosphere conditions are created inside the packages by the commodity itself and/or by active modification. Commodity generated or passive MA (Modified Atmosphere) is evolved as a consequence of the commodity’s respiration. The active modification involves creating a slight vacuum inside the package and replacing it with a desired mixture of gases, so as to establish desired EMA (Equilibrated Modified Atmosphere) quickly composed to a passively generated EMA. Another active modification technique is the use of carbon dioxide or ethyl absorbers (scavengers) within the package to prevent the build-up of the particular gas within the package. This method is called active packaging. Compounds like hydrated lime, activated charcoal, magnesium oxide are known to absorb carbon dioxide while iron powder is known as a scavenger to carbon dioxide. Potassium permanganate and phenylmethyl silicone can be used to absorb ethylene within the packages. These scavengers can be held in small sachets within the packages or impregnated in the wrappers or into porous materials like vermiculite. For the actively respiring commodities like fruits and vegetables, the package atmosphere should contain oxygen and carbon dioxide at levels optimum to the particular commodity. In general, MA containing between 2-5% oxygen and 3.8% carbon dioxide have been shown to extend the shelf life of a wide variety of fruits and vegetables. If the shelf life of a commodity is one day under CA storage, then the shelf life of a commodity at 20-25OC by employing MAP, will get doubled, whereas refrigeration can extend the shelf life to 3, and refrigeration combined with MAP can increase it to four days. Few types of films are routinely used for MAP. The important ones are polyvinyl chloride, (PVC), polystyrene, (PS), polyethylene (PE), and polypropylene (PP). The recent developments in coextrusion technology have made it possible to manufacture films with designed transmission rates of oxygen.