The packaging of food products is an integral part of the marketing and distribution process. The packaging materials used for food items depend on various factors like production cost economics, environmental factors, end-use requirement, and type of food. In general, packaging materials for nutrition can be classified into two major groups:
Traditional materials used for packaging foods.
Industrial materials used for packaging food items.
Types of Packaging Materials – Traditional Materials,
Leaves, vegetable fibers, and textiles are the traditional packaging materials for food items. Leaves and mats made of banana, bamboo, cane, and other such plant materials are used to pack fruits, vegetables, rice cakes, etc. Vegetable fibers like jute are the most suitable material for making gunny bags. Gunny bags are widely used as sacks by farmers to transport grains from farm to marketplace.
Paper made of wood pulp is extensively used for wrapping foods. This type of packaging is economical and biodegradable. The use of paper bags, cartons boxes, etc., has increased significantly during the last few decades. Paper containers are employed on a large-scale basis in wet markets to package poultry meats, fish, vegetables, etc.
Types of Packaging Materials – Industrial Materials,
The use of industrial materials for packaging foods is a recent trend. The most commonly used industrial materials are:
- Paper and Cardboard
- Flexible Plastic Films
Metals like tin, aluminum, copper, etc., are used for packaging foods. Tin-plated steel cans have been used as containers for many years now. Tin, aluminum, and copper are excellent heat conductors and offer complete protection against oxidation. In addition to these metals, plastics made of cellulose acetate, etc., are also extensively employed as containers for packed foods.
Paper and Cardboard
Paper is the most widely used packaging material in the world. It is made of wood pulp or cotton fiber. Paper is inexpensive, lightweight, robust, moisture-proof, and safe for use in food items. The paper obtained from wood pulp is called board stock, while those obtained from cotton are called bag boards. Paper is manufactured in sheet form or corrugated form. The corrugated types are widely used for packaging foods. Cellulose acetate is also used extensively for making tea bags, coffee bags, etc.
Flexible Plastic Films,
Flexible plastic films are made of PVC (Polyvinyl chloride), LDPE (Low-density polyethylene), HDPE (High-density polyethylene), PP (Polypropylene), etc. Flexible films are preferred as packaging materials for foods because they are light in weight, solid, and moisture-proof. In addition to this, they offer complete protection against oxygen and other atmospheric contaminants. The use of flexible plastic films for packaging food has increased in the last few decades. It is estimated that about 20% of all food items are packed in flexible film.
Cellulose is a high molecular-weight polymer obtained from plant tissues like cotton, timber, etc. Cellophane, sellotape, and various fabrics made of viscose fiber are used as packaging materials. Cellophane is the oldest and best known cellulosic film. It is manufactured from regenerated cellulose obtained by treating cotton or paper pulp with alkali and sulphuric acid under pressure.
Cellophane has a poor barrier to moisture vapor but provides excellent protection against light and ultraviolet rays. It is used for packaging fresh fruits and vegetables. Cellotape, a transparent film of regenerated cellulose, is widely employed as a wrapper for bread and pastries.
Polyethylene is the most widely used plastic in the world. Various polyethylene grades are employed to make plastic containers (polybags) and plastic films. Polyethylene possesses good gas barrier properties but has poor mechanical strength. It is used in thin sheets or bags for packing foods like bread, cakes, etc.
Polypropylene is light in weight and possesses good moisture barrier properties. It is expensive and has poor gas barrier properties. Nowadays, polypropylene is used for making flexible pouches or sacks of small capacity for containing dry foods like coffee powder, tea powder, etc.
Aluminium is a trendy material employed as a packaging material. The most commonly used containers for packing foods are aluminum cans. These cans have a sharp tapering of external and internal surfaces, enabling the can to stand upright and reducing the space inside the container. Aluminum cans offer complete protection against contamination and provide freshness to packed foods. However, they possess poor heat conductivity and low mechanical strength.
Tin is an alloy of copper and other metals like antimony, lead, etc. It has good heat conductivity and protection against oxidation. Tinned steel is widely used for making tin cans. The two essential properties of tins are their corrosion resistance and heat insulation property, which enable them to preserve the packed food for a longer time. However, tins are not moisture-proof and are very heavy in weight.
Glass containers are made by fusing soda ash (sodium carbonate) with silica sand (silicon dioxide) with or without lime. Glass is more robust than steel but is heavier in weight. Glass containers are not used for packaging foods because foods readily react with glass resulting in deterioration of food value.
Wooden boxes, barrels, etc., are widely employed as packaging materials for dry solid foods like cereals, pulses, etc. Rigid boxes are water-resistant, but they absorb moisture on coming in contact with the packed food. Wood offers safe packaging for dry foods, but it is not used in modern times because of its bulky nature and low protection to packaged food.
Leaves, vegetable fibers, and textiles,
Date palm leaves are used as packaging materials in some countries like Egypt. This material is pliable, light in weight, and waterproof, but it loses its qualities on coming in contact with food.
Paper is used as a wrapping material for packing foods like bread, pastries, etc. Paper possesses poor heat resistance and protection against damage or contamination. However, it can be printed on to provide the necessary information to the consumers.
In some countries, leather is used for making containers for packaging foods. This material has excellent flexibility and wear-resistance properties, but it is very bulky and cannot bear high temperatures. Leather absorbs food odor quickly and offers no barrier against loss of aroma or flavor. It is used to pack dry foods or foods with short storage life.
In some countries, earthenware is widely employed as a food container material. Earthenware is made of clay, and it possesses poor heat resistance and renders inflexibility and clumsy for handling purposes. Earthenware containers are porous and offer more resistance to penetration of gases, moisture, and odor. However, earthenware containers possess excellent insulation properties and retard food aromas and flavors loss.
The metal containers may be aluminum, tin plate, or steel. These containers can be used for packaging liquids and semi-solid foods. However, these containers cannot resist the odor or flavor of foodstuff.
Plastic materials are widely employed in packing foods like dairy products, beverages, etc., in aseptic processing plants in different parts of the world. These materials are inert to foodstuff and provide an excellent barrier against moisture, light, gases, etc., ensuring the freshness of packed foods. However, these plastics require special attention for handling in the packaging plants.