Importance of Packaging:

• Food packaging is an integral part of food processing and is the link between the food processor and the consumer.
• Packaging material protects foods from dehydration, oxidation, light, taste loss, environmental factors, and mechanical damage.
• Packaging provides facilities for storage, loading, transportation, handling for long periods of time for both the producer and the consumer.
• A package is a convenience item for the consumer, it can also be a cost-saving tool.

Methods of packaging / Packing:

(1) Edible film packaging:

An edible film or coating can be defined as only a thin continuous layer of food material, which is formed on or between food substances or food components. It is an integral part of a packaged food, which can be eaten as part of a whole food product. The selection of materials for use in food packaging is based on the properties of acting as a barrier to moisture and gases, mechanical strength, physical properties, and resistance to microbial growth. Materials used for food packaging include lipids, proteins, and polysaccharides, or a combination of any or all of these.

The most common form of coating fruits and vegetables is a wax coating to prevent respiration, dehydration, and aging. The selected food films should meet the requirements such as Physico-chemical and microbial stability, good sensory properties, high carrier, and mechanical capacity, toxic-free and safe for health, simple technology, non-polluting, and low cost of material and process.

(2) Modified humid packaging:

Mostly used for highly perishable items such as green leafy vegetables. Humid packaging systems are designed to control not only dehydration but also condensation. The use of water absorbers such as CaCl₂, sorbitol, or xylitol in the package or packaging with good permeability is able to provide the required modified humidity system.

(3) Protective packaging:

Protective packaging is the term used for packaging that is primarily designed to protect the product rather than for appearance or presentation, so is usually used in outer containers that are intended for sale by the manufacturer. Used inside the container to transport goods to the point of sale. For example, nylon barrier, sealed bubble packaging.

(4) Shrinkwrap / Individual seal packaging:

Individual seal packaging uses heat-shrinkable wrappers (usually HDPE) that are wrapped with hot air around individual units of fruits and vegetables. Hot air shrinks the packaging cover. This packaging delays ripening by the micro-environment that surrounds the product. This packaging acts as a good barrier to water.

It also prevents the spread of disease from one product to another, improves product handling and hygiene, and facilitates the pricing and labeling of individual products. However, problems with gas exchange and high RH can result in a foul odor in the product.

(5) Active packaging:

Another way to modify the environment of the pack is to use “active packing”. That packaging is said to be “active” when it serves some desired role as well as providing a passive barrier to the external environment. The goal of this type of packaging is to create a more perfect match of package properties to food requirements. A variety of materials are used for this purpose. Active packaging can be made using oxygen scavengers, carbon-di-oxide absorbers/emitters, ethanol emitters, and ethylene absorbers. A suitable absorbent material is placed alongside the fresh produce. Which contributes to the extension of the shelf life of fresh produce.

(6) Vacuum Packaging:

Vacuum packaging provides a comprehensive barrier against oxidation, corrosion, moisture, drying, dust attraction by electric charge, ultraviolet rays and mechanical damage, fungal growth or destruction, etc. This technique is very useful for tropical countries with high atmospheric humidity.

In vacuum packaging, the product to be packaged is put into a vacuum bag, which is then emptied of air by placing in a vacuum chamber and then hermetically sealed to create a barrier against air and moisture. If some products cannot tolerate atmospheric pressure due to the vacuum inside the package, the packages are then filled with inert gases such as nitrogen and CO₂ after being emptied.

Vacuum packaging prevents food from burning in the freezer by preventing exposure to cold, dry air.

(7) Controlled Atmosphere Packaging (CAP)

It refers to a storage environment that differs from the normal environment in composition in which the constituent gases are precisely adjusted to specific concentrations and maintained during the storage and distribution of perishable foods. Controlled atmosphere storage involves continuous measurement of the composition of the atmosphere and injecting suitable gases or gas mixtures into it when needed. Therefore, the system requires artificial equipment to monitor gas levels and is therefore only practically for refrigerated bulk storage or shipment of items in large containers. If the composition of the environment in the CA system is not closely controlled or if the storage environment is modified incorrectly, there is a risk of product degradation.

(8) Modified Atmospheric Packaging (MAP)

Unlike CAP, MAP has no means to precisely control atmospheric components at a specific concentration once the package is tightly closed. A modified environment state is created by a commodity inside the package or by active modification. Passive MA develops as a result of the respiration of the commodity. The active modification involves creating a slight vacuum inside the package and replacing it with the desired mixture of gases so that the desired EMA (Equilibrated Modified Atmosphere) can be quickly created from a passive MA. Another technique is the use of carbon dioxide or ethyl scavengers within the package to prevent the build-up of the special gas within the active modification package. This method is called active packaging. In addition to these, compounds such as hydrated lime, activated charcoal, magnesium oxide are used to absorb carbon dioxide, potassium permanganate and phenyl methyl silicon can be used to absorb ethylene within the package. These absorbents can be placed in small pouches or wrappers within the package. For active respiration items such as fruits and vegetables, the concentrations of oxygen and carbon dioxide in the package’s environment must be appropriate for them. In general, the concentration of 2-5% oxygen and 3.8% carbon dioxide for fruits and vegetables in MA packaging extends the shelf life. If the shelf life of an item is one day in CA storage, using MAP will double the shelf life of an item at 20-25 °C, while refrigeration can extend the shelf life to 3 days, and combined with MAP and Refrigeration can extend this to four days. There are necessarily certain types of films used for MAP. These include polyvinyl chloride, (PVC), polystyrene, (PS), polyethylene (PE), and polypropylene (PP).