Home > Advantages and disadvantages of the packaging materials, effects of these materials on packed commodities

Advantages of different packaging materials & effects of these materials on packed commodities:

Retortable pouches

The pouches, trays, and tubs are always multilayer laminate structures that contain different polymers which provide heat resistance, strength, and toughness (PET), pierce and pinhole resistance (nylon), oxygen barrier (EVOH, nylon or PVDC) and (for the pouches and trays) heat sealability (PP). An aluminium foil layer often serves as the moisture and oxygen barrier in pouches. The retortable paperboard cartons have external and internal PP layers that are impermeable to liquid and allow heat sealing, along with an internal aluminium layer that provides a gas and light barrier.

Advantages of retortable pouches

• less energy is required to manufacture pouches compared with cans
• transport of empty containers is cheaper (85% less space required than cans)
• packaging is cheaper than equivalent can and with carton cost is about the same
• filling lines are easily changed to a different size
• rapid heat penetration and faster process results in better nutrition/flavour
• contents are ambient shelf stable – no refrigeration is required
• packed pouch is more compact requiring about 10% less shelf space
• less brine or syrup used, pouches are lower in mass and cheaper to transport
• fast reheating of contents by immersion of pack in hot water. No pots to clean
• opens easily by tearing or cutting
• ideal for single portion packaging and serving size control
• retort pouch materials are non-corrosive
• convenient for outdoor leisure and military rations use.

Glass

Glass is made by mixing several naturally-occurring inorganic compounds at a temperature above their melting points. The molten mixture is then cooled to produce a non-crystalline, amorphous solid. The main ingredient is silica (sand) (SiO2) that serves as the network-forming backbone of the glass. However, silica has a very high melting temperature, and molten silica has high viscosity that makes it difficult to form into shapes. Adding soda (Na2O) modifies the silica network by disrupting some of the Si-O bonds, with resulting lower melting temperature and viscosity but reduced resistance to dissolving in water. Thus, lime (CaO) is added as a network stabilizer, with the result that durability is increased but tendency to crystallize is also increased. Finally, alumina (Al2O3) is added as an intermediate to resist crystallization. Minor amounts of colorants are added to produce colored glass, including chromium oxide for green, cobalt oxide for blue, nickel oxide for violet, selenium for red, and iron plus sulfur and carbon for amber. Amber provides the best protection for light-sensitive foods and beverages, transmitting very little light with wavelength shorter than 450 nm.

Advantages of Glass

• Inert
• Total barrier to
• Gas
• Water vapor
• Aroma
• Good compression resistance
• Good heat resistance
• Allow viewing of product
• Microwavable
• Customer perception of high quality
• Reclosable
• Recyclable
• Refillable

Metals

Like glass, steel and aluminium are total barriers to gases, water vapor and aromas. Both also have good heat resistance and can withstand physical and thermal shock. Because of steel‘s greater strength, it is used more often in the thermal processing of foods. Neither steel nor aluminium is as inert as glass; thus, both must be coated to avoid interactions with the foods they contain. Tin or chromium is used to coat steel, usually followed by a coating with a polymeric lacquer (enamel). Aluminium is coated directly with a lacquer. Other advantages of metal containers are exclusion of light from food products that are light-sensitive and their recyclability.

Advantages of Metal Containers

• Total barrier to
• Gas
• Water vapor
• Aroma
• Good compression resistance
• Good heat resistance
• Good thermal and physical shock resistance
• Light protection
• Recyclable

Plastic

The most commonly used thermoplastic polymers are inexpensive, and their conversion into food packaging is also relatively inexpensive. These plastics can be molded or extruded into a wide range of flexible, semi-rigid and rigid containers that are lightweight, noncorrodible, shock-resistant, and heat-sealable. Most are transparent and some are microwaveable. Certain plastics have high enough heat resistance that they can be hot-filled, retorted and/or used in a conventional oven. Finally, the most commonly used plastic semi-rigid and rigid containers are recyclable. Similar to glass and metal, plastic properties have improved over the years so that less material is necessary for making containers with acceptable integrity.

Advantages of plastics

• Inexpensive materials
• Inexpensive conversion to packaging
• Versatile
• Flexible
• Rigid
• Semi-rigid
• Moldable
• Light-weight
• Noncorrodible
• Shock-resistant
• Heat-sealable
• Transparent
• Can be pigmented
• Microwavable (some)
• Good heat resistance (some)
• Recyclable (some)

Paper

Paper is a quite versatile material, utilized in flexible, semi-rigid, and rigid packaging. It is made into a wide variety of single- and multi-wall bags. It can also be made into a thicker stronger structure (>0.012 in. /0.03 cm) called paperboard (Pb), which is made into cartons and boxes that provide mechanical protection for many foods. The paperboard can be converted to an even stronger material called corrugated paperboard that is converted into boxes used for logistics (tertiary and quaternary packaging). Most types of paper provide a partial or complete barrier to light. It can also be manufactured into transparent and clear materials. The starting material of paper, wood, is a renewable resource, and paper is recyclable and biodegradable.

Advantages of Paper Packaging

• Versatile
• Rigid
• Semi-rigid
• Flexible
• Mechanical protection
• Logistics functions
• Barrier to light
• Renewable resource
• Recyclable
• Biodegradable

Disadvantages of packaging materials & effects of these materials on packed commodities:

Glass 

Glass is one of the oldest manufactured materials and one of the first manufacturing businesses in the New World. Nonetheless, glass still serves as an important packaging material for food. The disadvantages of glass include its weight and vulnerability to fracture from thermal shock (rapid temperature change) and physical shock. In recent years, advances in the science and technology of glass have resulted in lighter, stronger glass containers. For those food products vulnerable to light-catalysed reactions, glass‘s transparency to light is another disadvantage. Use of light-absorbing colorants in the glass, as well as glass container labels and direct printing on the glass, will affect the transmission of light.

Disadvantages of glass

• glass is a heavy packaging material than others.
• breakage and subsequent loss of product
• hermetic seal that is more easily compromised
• the increased possibility of broken glass contaminating the finished product
• color changes of the product due to exposure of light
• expensive food packaging material

Metals 

The disadvantages of metal containers include their multi-step manufacture, weight (particularly steel), and (for some foods) lack of transparency. In recent years, advances in the science and technology of these metals have resulted in lighter, stronger metal containers.

Disadvantages of metal

• metal is corrosive material, can affect the quality of food
• metal is moderately heavy packaging material.
• Can‘t see the food content after packaging
• Due to multi –step can manufacturing process, can making is time taking process
• Metal can react with the food material

Plastic 

Plastics are high molecular weight polymers that can be molded into desired shapes such

as films, trays, bottles, and jars using heat and pressure. Plastics do not provide a total

barrier to gases, water vapor, and aromas. The permeabilities of a given plastic material to

water vapor, oxygen, carbon dioxide, and aromas depend on the particular polymer

composition and structure. This must be considered when selecting a plastic for a specific

application and desired shelf life. Plastics are often combined in layers, to take advantage

of the unique barrier properties of each polymer. Similar to glass, plastic container transparency to light can be detrimental to foods vulnerable to light-catalyzed reactions. Pigmenting, labeling or direct printing of plastic containers can reduce this problem for sensitive food products. Plastic materials do not have the compressive strength of glass or metal, and only a few plastics have high enough heat resistance for heat processing or preparation of foods. Plastic additives and any residual monomers have potential for migrating into foods. Thus, much attention and testing are devoted to minimizing this possibility. On the other hand, food components such as aromas and flavors can sorb into plastic packaging, with resulting loss of food quality. Finally, most plastic materials used in food packaging are not recyclable. Fortunately, these are used in lower quantities than recyclable plastic containers.

Disadvantages of plastic 

• Permeable to
• Gas
• Water vapor
• Aroma
• Monomers
• Additives
• Food components can sorb into plastic
• Low compressive strength
• Lack heat resistance (some)
• Not recyclable (some)

Retortable Pouches 

The main disadvantage of retortable pouches, trays, tubs, and cartons is more difficult recycling. Pouch integrity and sealing have also been concerns that are addressed through vigorous package inspection and regulation. National Food Processors Association (NFPA) recommends several tests, including squeeze test, burst test, and seal tensile strength. Seals can also be tested using a dye penetration test or headspace gas composition test. Retorting of pouches and trays must include overpressure and critical control of pressure changes to prevent seal failure. Also, special racks or trays are incorporated in the retort to restrain pouches to a defined thickness for consistent heat transfer.

Disadvantage of retortable pouches 

• to achieve equivalent cannery production efficiency, a major investment in new capital equipment for filling and processing is required
• production speed on single filler/sealer is usually less than half that of common can seamers
• new handling techniques have to be adopted and may be difficult to introduce
• heat processing is more critical and more complex
• to retain rapid heat penetration there are limitations on pouch dimensions
• some form of individual outer wrapping is usually required, adding to cost
• being non-rigid products such as some fruits lose their shape
• being a new concept, education of the consumer as to correct storage and use is required during marketing.

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