FNB News - Food: Packaging materials and packaging systems

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Food: Packaging materials and packaging systems

Thursday, 05 March, 2015, 08 : 00 AM [IST]

Gulzar Ahmad Nayik and Ishrat Majid

Nearly 90 million tonne of food is wasted annually in Europe, according to the data available on official website of European Commission.

Further,12% of fruits and vegetables, 9.5% of seafood, and 4% of meat are lost in distribution and retail. Globally 1/3rd of the food (1.3 billion tonne) for human consumption is wasted. In view of this the basic aim of food packaging is to reduce food loss and increase shelf life and quality of food.

Hence, it is important for food packaging to contain food in a cost-effective way to meet consumer desires, maintain food safety, and minimise environmental impact.

Interestingly, packaging and storage of food is as old as human civilisation. Earthenware pots, wood, and glass have been used for this purpose thousands of years ago.

Having said that, let us look at what packaging is all about. Packaging is defined as the science, art or technology of protecting products for distribution, storage, sale, and use. It may be further defined as a means for delivering products to the consumer safely and cost effectively and in accordance with the marketing strategy.

Common requirements of effective food packaging material
It should protect food from contamination whether physical, chemical or biological.

It should maintain quality of food contained in it.
It should be inert, non-toxic, easy to open and resistant to hazards.
It should act as a barrier against loss or gain of moisture and oxygen.
It should bear the information regarding nature of contents, nutrition.

The other function of package is to protect or preserve the food from external contamination which includes extending the shelf life, retardation of deterioration and, maintenance of quality of food. Packaging protects the food from various environmental influences such as temperature, heat, light, micro-organisms, insects, rodents, dirt, and dust. The choice of packaging food depends mostly on nature of food. As we know foods are complex substances that are composed of water, fats, carbohydrates, proteins, minerals, vitamins and other organic substances. This composition of food varies from food to food, e.g. meats are mainly composed of proteins while fruits are mainly composed of water and sugars. Thus composition of food determines the choice of packaging and it determines how well it withstands against different types of spoilage.

Packaging materials
Traditional packaging materials
Food packaging began when ancient man started covering the food with leaves which he could consume next day. Following are few traditional packaging materials:

Leaves: Banana leaves are often used to cover cheese like guava cheese. Pan leaves are used for wrapping spices in India.

Baskets: Bamboo baskets of different shapes and sizes are used for number of perishable commodities. They are suitable for head load only and for very short distance transportation only. Baskets are not strong enough to withstand rough handling.

Treated Skin: Leather has been used for many centuries. Water and wine are frequently stored and transported in leather containers which are made up of camel, pig and kid goat hides. Solidified sugar and manioc flour are also packed in leather cases and pouches.

Wooden Crates: They are relatively resistant to different weather conditions and water. Wooden crates are often reused and have a higher efficiency for larger fruits, e.g. watermelons. Most crates have good ventilation.

Apart from traditional packaging materials most of the food commodities are generally packed in following packaging materials:

Paper and Board: Near about 35% of all food material are used in paper and board packaging material. Paper and board are easily available; cost is low and has good strength. Generally apple, oranges, mangoes are packaged in such materials.

Metal Cans: Most of the beverages whether alcoholic or non-alcoholic are packaged in metal cans.

Glass Containers: Being transparent, recyclable and reusable, glass containers are used in wide range of foods like instant coffee, dry mixes, spices, dairy products, jams and marmalades, spreads, syrups, and pickles.

Plastics: Plastics are widely used as food packaging material because they are light weight, low cost, flowable and mouldable. Nearly 50% of food material is packed in plastic packaging in Europe. Plastics are used in number of forms like plastic rigid containers (bottle, jars, trays), and flexible plastic films (bags, sachets, pouches). Plastics are also used in laminations with other materials such as paper and paperboard, regenerated cellulose film (RCF), aluminium foil, to increase the properties. Various types of plastics used in food packaging industry include

Polyesters (PET, PEN, PC)
Ethylene vinyl acetate (EVA)
Polyamides (PA)
Polyvinyl chloride (PVC)
Polyvinylidene chloride (PVdC)
Polystyrene (PS)
Acrylonitrile butadiene styrene (ABS)
Ethylene vinyl alcohol (EVOH)
High nitrile polymers (HNP)
Styrene butadiene (SB)
Polymethyl pentene (TPX)
Fluoropolymers (PCTFE/PTFE)
Polyvinyl acetate (PVA).
Polyethylene (PE)
Polypropylene (PP)

Apart from these, wood is also used as it provides resistance to different weather conditions. Wooden crates are often reused and have a higher efficiency for larger fruits, e.g. watermelons. Most crates have good ventilation.

Fig. Market share of various packaging materials

Packaging systems
Various active packaging systems
1. Active Packaging: According to Day (1989), active packaging refers to the incorporation of certain additives into packaging film or within packaging containers with the aim of maintaining and extending product shelf life. Active packaging includes oxygen scavengers (acid, catechol, glutathione, ascorbate salts), humidity absorbers (silica gel), ethylene absorbers (Potassium permanganate), carbon dioxide emitters, and ethanol emitters.

2. Antimicrobial active packaging system: Surface microbial spoilage is the primary cause of shelf-life termination of fresh fruits, vegetables and meat. Some reasons for microbial contamination are transportation, packaging, uncontrolled harvesting and processing operations. Adding antimicrobial agents such as hydrogen peroxide, peroxyacetic acid, ozone, chlorinated water, and plant extracts into the washing water demonstrates effective antimicrobial activity.

3. Intelligent Packaging: It is also called as smart packaging. This type of packaging exists as a monitoring system which monitors some properties of the food that it encloses and is able to inform the manufacturer, retailer and consumer of the state of these properties. Once the package is tampered, the seal or the label may undergo a permanent colour change while intelligent packaging perhaps will be able to inform a consumer of an event that occurred such as package tampering that may save their life. Intelligent packaging systems include Time Temperature Indicators (TTIs), Oxygen and Carbon dioxide Indicators.

4. Modified Atmosphere Packaging: Modified-atmosphere packaging (MAP) of food refers to the technique of sealing actively respiring fresh foods in an atmosphere of low O2 and high CO2 levels. MAP of fresh foods like fruits, vegetables, fish, and meat is a successful technology for maintaining quality for prolonging the shelf-life period during storage and marketing. The MAP is one of the successful packaging technology in increasing shelf life of fresh fruits and vegetables.

5. Edible films: Increasing consumer demand for safe, convenient, and stable foods and also awareness of the negative environmental impact of non-biodegradable packaging waste has increased the interest and research activity in edible packaging. Any type of thin material used for enrobing (i.e. coating or wrapping) various food to extend shelf life of the product that may be consumed together with food with or without further removal and provides a barrier to moisture, oxygen and solute movement for the food is considered an edible film or coating. Various types of edible coatings and films have been used in fruits and vegetables viz. polysaccharides based films & coatings (cellulose, starch derivatives, pectin derivatives, seaweed extracts, exudate gums, microbial fermentation gums and chitosan), proteins-based films and coatings (casein, whey protein, gelatin/collagen, fibrinogen, soy protein, wheat gluten, corn zein, and egg albumen), lipid-based edible films & coatings (waxes).

Other compounds have been used to form coatings for fruits, such as pullulan, gellan, aloe vera, cactus–mucilage and fruit puree. Despite the great benefits from using edible coatings, commercial applications of this technology on a broad range are still very limited. Enhancement of the water resistance, mechanical and barrie r properties of biopolymer films still need improvement.

Future direction of food packaging
1. Packaging must be recyclable, reused and ecofriendly; 2. Developing food packaging system for space food; 3. The primary goal of food packaging should continue to be maintaining the safety, wholesomeness, and quality of food; and 4. The impact of packaging waste should be minimised.

(The authors are research scholars at dept of food engineering & technology, Sant Longowal Institute of Engineering & Technology, Longowal, Sangrur, Punjab. They can be contacted at gulzarnaik@gmail.com)