30 Packaging Techniques

S. Deena

1. INTRODUCTION

Food packaging is a science of making food materials look attractive to the consumer and at the same time keeping the food fresh and easy to eat. Food packaging is done with the objective of protecting food, resisting tampering and providing special physical, chemical or biological needs. The food package should bear a nutrition fact label and other relevant information about food being offered for sale.

Food processing and packaging industries spend approximately 15% of the total variable costs on packaging materials. Innovations in food and beverage packaging have seen development due to industrial processing of food and lack of time to prepare food from fresh ingredients. The innovations are driven by consumer needs and demands that are influenced by changing global trends such as increased life expectancy and abundant and diverse food supply. The emerging innovations to name a few are active and intelligent packaging (such as oxygen scavengers and moisture control agents), packaging mechanisms that control volatile flavors and aromas and advances in food packaging distribution (radio frequency identification and electronic product codes)

2. OBJECTIVES

After completion of this topic you will be able to understand

•  the functions of food packaging
• materials used for food packaging
• the types of food packaging and machinery used
• the modern and futuristic trends in food packaging

3.1. FUNCTIONS OF FOOD PACKAGING

The major objective of food packaging is to satisfy industry requirements and consumer requirements by containing food in a cost-effective way, maintaining food safety and minimizing environmental impact. Packaging not only protects food from outside influences and damage but also provides consumers with information on ingredients and nutrition. The following points will give a detailed account of the functions of food packaging:

• Protection -Packaging protects food from physical, chemical and biological influences. Packaging of food helps to protect it physically from mechanical damage which includes shock and vibration during transportation. It helps to protect chemically by minimizing changes in composition of food due to environmental influences such as exposure to oxygen, moisture or light. Packaging also protects food biologically by providing a barrier to pathogenic micro organisms, insects and rodents and thereby prevents disease and spoilage.
• Barrier protection –The primary function of packaging is to keep the food clean, fresh, and safe for the intended shelf life. Packages offer a barrier to food from oxygen, water vapor, dust, etc., Some packages contain oxygen absorbers that help to the extend the shelf life of the product. In some food packages modified or controlled atmospheres are maintained.
• Containment or agglomeration – In order to facilitate efficient handling small items of food are grouped together in one package. For example liquids, powders, and granular materials can be grouped together in one package.
• Transmission of information – It is mandatory by law to provide certain information to consumers. Packages and labels help to communicate such information as product identification, ingredients used, nutritional value, net weight, directions for use, pricing, manufacturing date and expiry date.
• Marketing – Manufacturers use packages and labels as an effective marketing tool to promote potential buyers to purchase the product. An important and constantly developing phenomenon for several decades has been designing of packages. Graphic design and marketing communications are applied to the surface of packages. The sales of a product in a competitive environment can be increased by designing unique or innovative packages.
• Security – There may be security risks during shipment of food products. Such risks can be reduced to a great extent by appropriate packaging techniques. In order to prevent tampering packages can be made tamper resistant and can also have tamper-evident features which will indicate tampering. Packages can be designed in such a way to reduce the risk of pilferage. Some packages may have pilfer-indicating seals. Packages may have authentication seals which indicate that the contents are genuine. Packages can also have dye packs, RFID tags or electronic article surveillance tags which are all anti-theft devices. These devices can be activated or detected at exit points and require specialized tools to be deactivated.
• Convenience – Certain features which include convenience in distribution, handling, stacking, display, sale, opening, reclosing, use, reuse and disposal can be incorporated in packages. Packaging in oven-safe trays, boil-in bags and microwave cooking bags have made cooking very convenient to the consumers.
• Portion control – This can be ensured by use of single-serving packages. For example bulk commodities such as salt can be divided into packages of a suitable size for individual households. Packaging also helps in inventory control. For example milk sold in sealed one-liter bottles ensures better control than milk sold in the bottles brought by consumers to fill themselves.

    3.2. MATERIALS USED IN FOOD PACKAGING

Successful packaging techniques can be adopted only if the package material and design is selected in such a way that it will address issues such as characteristics of product, marketing considerations, environment and waste management and cost. The design and construction of a package plays an important role in determining the shelf life of a food product. The precise selection of packaging material and packaging technology helps to maintain the quality and freshness of food products during distribution and storage. The following are some of the materials that are used for packaging of food products

3.2.1. Glass – Glass has been traditionally used as packaging material for food products for many years as it is odourless and chemically inert with almost all food products.

Advantages

• Glass maintains the freshness for a long period of time without damaging the taste or flavor of the product as it is impermeable to gases and vapors.
• Glass can be used for heat sterilization of both low- acid and high-acid foods as it has the ability to withstand high processing temperatures
• Glass can be produced in a variety of shapes as it is rigid and provides good insulation
•  Glass is transparent and so it allows consumers to see the product
• Glass packaging is reusable and recyclable and so it is beneficial to the environment Disadvantages
• There is additional cost of transportation as glass is heavy in weight
• Glass is susceptible to breakage due to internal pressure, impact or thermal shock as it is brittle

3.2.2. Metal – Metal is the most adaptable of all packaging materials as it has excellent physical protection and barrier properties, has decorative potential, has fine consumer acceptance and is recyclable. The most common metal used in packaging food products is aluminum.

• Aluminum– It is used commonly to make cans, foil and laminated paper or plastic packaging .It is used primarily for light packaging of soft-drink cans, pet food and seafood.
• Aluminum foil -This s available in a wide range of thickness. Thin aluminium foils are used to wrap food and thicker ones are used for trays. Aluminum foils are used extensively as packaging material for food products as they provide excellent barrier to moisture, air, odor, light and microorganisms.
• Laminates and metalized films – Binding of aluminum foil to paper or plastic film to improve its barrier properties is known as lamination. Lamination to plastic enables heatsealability. However, the seal does not completely bar moisture and air. Laminated aluminum is generally used to package high value foods such as dried soups, herbs and spices as it is comparatively expensive.

Advantages

• Aluminum provides an excellent barrier to moisture, air, odor, light and microorganisms
• Aluminum has got good flexibility and surface resilience
• It has got excellent formability as well as outstanding embossing potential
• It can be recycled easily because it can be easily reclaimed and processed into new products
• Aluminum is high in cost compared to other metals
• It can be used only for making seamless containers as it is unable to be welded

3.2.3. Plastics

Plastics are used extensively for food packaging due to its properties. Thermoplastics can easily be molded into products such as bottles, jugs and plastic films and so they are ideal for food packaging. Thermoplastics can be melted and reused as raw materials for production of new products as they are recyclable.

Advantages

• Plastics are flexibile in design as they are fluid and moldable.
• Plastics are inexpensive and light in weight
• Plastics are chemically resistant and have a wide range of physical and optical properties
• Many plastics are heat sealable and easy to print

Disadvantage

• Plastics have variable permeability to light, gases, vapors and low molecular weight molecules.

3.2.3.1. Types of Plastic

• Polyethylene- A simple and inexpensive type of plastic is polyethylene. There are two categories of polyethylene: High-density used to make bottles for milk, juice, water; liners for cereal box and retail bags. Low-density polyethylene is used to pack bread and frozen foods, flexible lids and squeezable food bottles. Among plastic packages, the ones most recycled are the high-density polyethylene containers, especially milk bottles.
•  Polyethylene terephthalate (PETE) – PETE is used widely as packaging material for many food products, particularly beverages, mineral waters and carbonated drinks as it has good resistance to heat, mineral oils, solvents and acids. PETE bottles transparent like glass, light in weight, can retain carbonation and is shatter resistance.

3.2.4. Paper and paperboard

3.2.4.1. Paper – The different types of paper used in food packaging are:

• Kraft paper-This is used commonly used to make bags or wrappers for packing flour, sugar and dried fruits and vegetables.
•  Sulfite paper- This is used to make small bags or wrappers for packaging biscuits and confectionary.
• Greaseproof paper- This is used to wrap snack foods, cookies, candy bars and other oily foods.
• Glassine-This is used as a liner for biscuits, cooking fats, fast foods and baked goods.
•  Parchment paper-This is used to package fats such as butter and lard.

   3.2.4.2. Paperboard – Paperboard which is thicker than paper and made in multiple layers is used to make boxes, cartons and trays for shipping and not for direct food contact.

3.2.4.3. Paper laminates- Laminated paper is used to package dried products such as soups, herbs and spices.

3.3. TYPES OF FOOD PACKAGING

The following table gives an overview of the type of packaging, type of container and examples of foods packed. Primary packaging is the main package that holds the food that is being processed. Secondary packaging combines the primary packages into one box being made.

Tertiary packaging combines all of the secondary packages into one pallet.

3.4. TYPES OF PACKAGING FOR FOODS AND BEVERAGES

There is a demand in the market for a method of packaging natural products. To fulfill this demand, aseptic method of packaging has been developed. The following are the types of packaging for foods and beverages:

3.4.1. Cans

This type of packaging which uses aseptic techniques is adopted by 90% of the market. The foods that are canned for commercial purpose are generally cooked prior to being placed in the can in order to prevent E. coli contamination. Foods that are canned range from meat to vegetables to fruit to refrigerated bread dough.

Packaging in cans has the following disadvantages:

• It is expensive
• Empty cans will occupy more space
• The cost of manipulation is high
• There is loss of quality as foods have to be filled in cans when hot.

3.4.2. Aseptic Drum

Aseptic drums created a revolution in packaging as the drums were a substitute for 5 Kg. cans used widely in industrial sectors. Aseptic drum is a high technology drum made of cold rolled steel sheet and internally lined with non-plastic, food grade, PVC film. These drums are used primarily for the packaging of liquid and semi-liquid food products for example juices, purees, pulps and concentrates. Aseptic drums help to maintain the quality of the product and can be re-used several times once they are emptied.

However the disadvantages of using aseptic drums are:

• They are expensive
• There is loss of quality of foods as they must be filled in while still hot
• It is very difficult to cool once it is filled due to its dimension
• Lot of space is occupied by empty drums in store rooms
• The cost of manipulation is high

3.4.3. Tetra Packs

This kind of packaging is very common and is widely used in the milk, dairy and beverage industries.

The disadvantages of using tetra packs are:

• It cannot be used for packaging volume/bulk foods in the industry
• It cannot be used for filling products with fibers or particulates

3.4.4. Foil Packs

An innovative method of commercial food packaging is foil wrapping. Foil wraps are pouches which are filled and then sealed at the bottom and top with a heat seal. Foil packaging allows the foods to be sealed in the package without losing any moisture that may still be in the food. Examples of foil packed foods are dried fruits, baked goods and grain products.

3.4.5. Glass bottles, Jars and PET

The use of glass bottles is decreasing rapidly in the market for the aseptic filling of juices and beverages. Instead, use of PET bottles is developing very fast.

3.4.6. Frozen foods

The quality of foods can be preserved by freezing. Vegetables that are frozen should be thoroughly cleaned and cooked if that is appropriate. Certain vegetables like tomatoes have to be cooked and pureed if it is to be frozen whereas corn can be frozen without being precooked however if the food is to be preserved completely, it should be filled in airtight packages to prevent freezer burn which can spoil the food.

The disadvantages of packed frozen foods are:

• Storage requirements
• Logistics

3.5. FOOD SAFETY REGULATIONS

It is mandatory to maintain Food Safety and to conform to regulations during processing, packaging, storage, transportation, sale, and use of food products. Certification programs such as the Global Food Safety Initiative can be used. The other regulations used may be specific to countries such as the norms of US Food and Drug Administration, US Department of Agriculture, European Food Safety Authority. The following regulations have to be adhered to in food packaging:

• Use of HACCP (Hazard Analysis and Critical Control Points)
• Follow protocols of verification and validation
• Use of good manufacturing practices
• Use of effective quality management system
• Use of track and trace system
• Follow requirements for content of label

4.1. PACKAGING MACHINERY

The following factors should be taken into consideration in selection of packaging machinery:

• technical capability
• requirement of labor
• safety of worker
• ease of maintenance
• reliability
• cost of machinery
• floor space required
• flexibility
• usage of energy
• quality of outgoing packages
• efficiency and productivity

4.2. TYPES OF PACKAGING MACHINERY

Packaging machines may be of the following types:

• Autocoding label and date verification
• Blister-, skin- and vacuum-packaging machines
• Capping, over-capping, lidding, closing, seaming and sealing machines
• Cartoning machines
• Case and tray forming, packing, unpacking, closing and sealing machines
• Cleaning, sterilizing, cooling and drying machines
• Conveying and accumulating machines
• Filling machines for liquid and powdered products
• Inspecting, detecting and check weighing machines
• Labeling, marking and product identification machines
• Wrapping machine

5.1. MODERN TRENDS IN FOOD PACKAGING

The latest trends and techniques in food packaging have improved the safety and quality apart from increasing the shelf life of foods. Some of the novel trends are:

• Smart indicators- The use of smart indicators on packages is on the rise. There are different indicators with different benefits for food producers, consumers and retailers.
• Temperature recorders- The use of temperature recorders which monitor products shipped in a cold chain using digital temperature data loggers to measure and record the temperature of food shipments is a modern trend in packaging.
• RFID- The use of Radio Frequency Identification to food packages benefits food producers and retailers by creating a real time visibility of their supply chain.
• Bioplastics-The use of plastic packaging is usually non-biodegradable. To overcome this newer bioplastics, films and products are being developed.
• Barcodes- The use of barcodes in food packaging ensures that the products are correctly packaged and date coded. This also helps to track the products throughout the distribution process.
• Flexible packaging- The use of flexible material such as paper, plastic film, aluminum foil and metallized films in food packaging is used.
• Nanotechnology- The use of nanotechnology in commercial food packaging makes the packaging thinner and biodegradable. Food storage bags that are “green” are available that helps to keep food fresher for a longer time.

5.2. FUTURE TRENDS IN FOOD PACKAGING

• Edible Packaging- In the future edible food packages will be available. For example an edible rice paper-wrapped candy is available in Japan.
• Micro packaging- A micro film which is thousands of times thinner than human hair has been invented which can be used for packaging food. This microfilm is more eco-friendly than plastic and has the preservation qualities of glass.
• Smart Packaging- Research is on about an innovative technology called “electronic tongue “that can “taste” food through sensors embedded in the packaging. If the food is contaminated or spoiled, the packaging will change color, alerting the consumer whether it can still be cooked or needs to be thrown out.
• Anti-microbial packaging- Research is on about anti-microbial packaging which will not only protect food from bacteria but will actively act against it. Packaging can be done in an anti-bacterial silver nano particle-coated paper that can fight to keep germs out of food.
• Water soluble packaging- Food can be packed in pouches that dissolve in water. The plastic film packaging which dissolves faster under hot water cannot be tasted when eaten. This technology can be used to package such liquid-friendly foods such as drink powders, cereals, soups and sauces.

6.  CONCLUSION

There have been great advances in the food industry in the packaging sector since its inception in the 18th century. As international trade expands, improvement in packaging techniques in India becomes significant. The basic objectives of food packaging are protection and preservation of a product, launch of new products or re-launch of existing products, perception of added-value to products or services and cost reduction in the supply chain. It is important to consider which materials and processes will best serve the market and enhance brand value. The advances in packaging techniques which have been driven by changing consumer preferences have led to improved food quality and safety. The new advances focus mainly on delaying oxidation and controlling moisture migration, microbial growth, respiration rates and volatile flavors and aromas. Nanotechnology will elevate food packaging to new heights in the future.

Bibliography

1. Jairus R. D. David, Ralph H. Graves, Thomas Szemplenski (2012). Handbook of Aseptic Processing and Packaging, CRC Press.
2. Gordon L. Robertson (3rd Edition). Food Packaging: Principles and Practice, CRC Press.
3. Richard Coles, (2ndd Edition). Food and Beverage Packaging Technology, Wiley Blackwell Press

Web link

• www.sciencedirect.com/science/book/9781855736757
• https://www.elsevier.com/…food-packaging-techniques
• www.eolss.net/sample-chapters/c10/E5-10-04-16.pdf
• https://en.wikipedia.org/wiki/Food_packaging