“Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of design, evaluation, and production of packages.”
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Functions of Packaging
Packaging is a means of providing the correct environmental conditions for food during the length of time it is stored and/or distributed to the consumer. A good package has to perform the following functions:
--> It must keep the product clean and provide a barrier against dirt and other contaminants.
--> It should prevent losses. Its design should provide protection and convenience in handling, during transport, distribution and marketing. In particular, the size, shape and weight of the packages must be considered.
--> It must provide protection to the food against physical and chemical damage (e.g., water and water vapour, oxidation, light) and insects and rodents.
--> It must provide identification and instruction so that the food is used correctly and have sales appeal.
--> And finally, the package is one of the greatest influences on a consumer’s decision to try your product.
The Ideal Food Package
The perfect food package has all of the following criteria:
--> compatible with food; protects against contamination from the environment; controls the product’s environment;
--> resists mechanical damage; sanitary; tamper-proof; attractive; convenient;
--> inexpensive; lightweight; environmentally sound;
--> functions as a preparation and/or serving vessel;
--> sells itself; identifies the product; and supplies the required information.
--> Textile containers have poor gas and moisture barrier properties and have a poorer appearance than plastics.
--> Woven jute sacks, which are chemically treated to prevent rotting and to reduce their flammability, are non-slip, have a high tear resistance, and good durability.
--> They are used to transport a wide variety of bulk foods including grain, flour, sugar and salt.
--> Wooden shipping containers have traditionally been used for a wide range of solid and liquid foods including fruits, vegetables, tea and beer.
--> Wood offers good mechanical protection, good stacking characteristics and a high weight-to-strength ratio. However, plastic containers have a lower cost and have largely replaced wood in many applications.
--> Wooden crates are imported for transporting fresh fruit and vegetables, fish etc. They are used to hold foods together and protect them from crushing, but otherwise offer little protection.
--> Earthenware is used worldwide for storage of liquids and solid foods such as curd, yoghurt, beer, dried food, honey, etc.
--> Corks, wooden lids, leaves, wax, plastic sheets, or combinations of these are used to seal the pots. If well sealed, it is a gas, moisture and lightproof container.
--> Unglazed earthenware is porous and is very suitable for products that need cooling e.g. curd.
--> Glazed pots are better for storing liquids e.g. oils, wine, as they are moisture proof and airtight, if properly sealed.
--> All are lightproof and if clean, restrict the entry and growth of micro-organisms, insects and rodents. One should ensure that the glazing of the earthenware does not contain lead.
--> Plastics differ in how effective they are as barriers to the various important gases—oxygen, carbon dioxide and water vapour. Selecting the right plastic packaging requires knowledge of how sensitive the product is to loss or absorption of these gases.
--> functions as a preparation and/or serving vessel;
--> sells itself; identifies the product; and supplies the required information.
Types of Packaging/ Packaging Materials
1. Textiles
--> Woven jute sacks, which are chemically treated to prevent rotting and to reduce their flammability, are non-slip, have a high tear resistance, and good durability.
--> They are used to transport a wide variety of bulk foods including grain, flour, sugar and salt.
2. Wood
--> Wood offers good mechanical protection, good stacking characteristics and a high weight-to-strength ratio. However, plastic containers have a lower cost and have largely replaced wood in many applications.
--> Wooden crates are imported for transporting fresh fruit and vegetables, fish etc. They are used to hold foods together and protect them from crushing, but otherwise offer little protection.
3. Earthenware
--> Corks, wooden lids, leaves, wax, plastic sheets, or combinations of these are used to seal the pots. If well sealed, it is a gas, moisture and lightproof container.
--> Unglazed earthenware is porous and is very suitable for products that need cooling e.g. curd.
--> Glazed pots are better for storing liquids e.g. oils, wine, as they are moisture proof and airtight, if properly sealed.
--> All are lightproof and if clean, restrict the entry and growth of micro-organisms, insects and rodents. One should ensure that the glazing of the earthenware does not contain lead.
4. Metal
Metal cans have a number of advantages over other types of container, including the following:
However, the high cost of metal and the high manufacturing costs make cans expensive. They are heavier than other materials, except glass, and therefore have higher transport costs.
Aluminium: This is commonly used in packaging, such as drinks cans, foils and laminates. It has a high value as a scrap metal with prices ranging from £650-750 per tonne. It can also be recycled economically - 20 recycled aluminium cans can be made with the energy it takes to manufacture one brand new one.
Steel: is a widely used packaging material for food, paint and beverage as well as aerosols. Recycling steel brings significant resource and energy savings. The current recycling rate for steel cans is 62%.
5. Glass
Advantages:
--> they are impervious to moisture, gases, odours and micro-organisms
--> they are inert and do not react with or migrate into food products
--> they are suitable for heat processing when hermetically sealed
--> they are re-useable and recyclable
--> they are resealable
--> they are transparent to display the contents
--> they are rigid, to allow stacking without container damage.
Disadvantages:
--> higher weight which incurs higher transport costs than other types of packaging
--> higher weight which incurs higher transport costs than other types of packaging
--> lower resistance than other materials to fractures, scratches and thermal shock
--> more variable dimensions than metal or plastic containers
--> potentially serious hazards from glass splinters or fragments in foods.
--> potentially serious hazards from glass splinters or fragments in foods.
6. Flexible Films
In general, flexible films have the following properties:
--> their cost is relatively low
--> they have good barrier properties against moisture and gases
--> they are heat sealable to prevent leakage of contents
--> they have wet and dry strength
--> they are easy to handle and convenient for the manufacturer, retailer and consumer
--> they add little weight to the product
--> they fit closely to the shape of the food, thereby wasting little space during storage and distribution.
Examples: Cellulose, Polypropylene , Polyethylene, Polystyrene, Polyvinylidene chloride
7. Coated Films
Films are coated with other polymers or aluminium to improve the barrier properties or to import heat sealability. For example, nitrocellulose is coated on one side of cellulose film to provide a moisture barrier but to retain oxygen permeability. A thin coating of aluminium produces a very good barrier to oils, gases, moisture, odours and light.
8. Laminates
Laminates combine the advantages of several materials into one. For example, one film may consist of paper, metal (foil) and plastic. In this case, paper is used for its low cost and strength, metal is added to prevent gas and/or light penetration, and a low-cost plastic is incorporated so the film can be heat-sealed. Laminates can often be more costly than other packaging alternatives, such as metal cans or plastics. Examples of laminates are Tetra Brik® drink boxes, potato chip bags, retort pouches and “ovenable” paperboard (paperboard that can be heated up to 400°F).
9. Paper
Food packages made from paper can be formed into simple or elaborate designs, because it is flexible and easy to work with. Other benefits to using paper include: light weight; generally inexpensive; and excellent surface for printing.
Because paper isn’t waterproof, its structural integrity is limited. That is, when paper gets wet, it becomes weaker. As a result, paper is restricted to certain applications when used alone. To overcome this problem, paper is often coated with polymers or lined withss foils. Types of paper packaging include:
• bags and pouches;
• folding cartons; and
• corrugated boxes.
10. Plastic
--> some of the more complex laminates can be very expensive.
- they can bend, crush or crack easily;
- some possess little heat resistance;
- they pick up dust easily; and
--> Plastics differ in how effective they are as barriers to the various important gases—oxygen, carbon dioxide and water vapour. Selecting the right plastic packaging requires knowledge of how sensitive the product is to loss or absorption of these gases.
Types of Plastic
- Thermoplastics: These can be re-formed into a desired shape after being melted. This type of plastic is used to produce plastic bags, pouches, bottles, trays and cups.
- Thermoset plastics: A thermoset plastic is very strong once formed, and will decompose before melting (that is, it won’t re-form). This type of plastic is commonly used for bottle caps and can coatings.
