Why We Need to Package Food and Add Protective Barriers

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In the packaging of food, it is necessary to create barriers in the form of laminates or laminate films. One of the main applications of a laminate film is to create a protective barrier — a line of defence against common sources of contaminants of food like gas and water vapour. By regulating these external factors, food can be kept under the best, most favourable storage conditions.
Although this barrier appears to be singularly thin and simple on the outside, its function requires it to be more complex in composition and arrangement. In fact, it can be multilayer and flexible in order to be effective. Don’t be deceived into thinking that all food packaging are created equal, because they are not all the same.
Its arrangement and composition
To achieve maximum protection, such complexity in structure translates into several layers of polymers and barrier coatings like polyvinylidene chloride (PVDC), polyvinyl alcohol (PVOH), and ethylene-vinyl alcohol (EVOH). Some common examples of polymers used include polyethylene and polypropylene, which are both polyolefins.
Taken all together, there is an underlying purpose for layering and combining these materials. Depending on its application, the substrate may be made of plastic film or some metallised layer like aluminium. By incorporating an EVOH barrier coating to the process, it is customised into a flexible laminate film. This makes the packaging less permeable to water.
Two types of protective barriers
First, it is necessary to have a water vapour barrier to keep food from either going dry in open air or absorbing moisture from the environment. When dehydrated, any cooked food that is dry tends to solidify and form lumps. Frozen food that absorbs water from the air will change in texture and lose its crunch.
Second, we need an oxygen barrier to lock in the freshness. It keeps protective gases in at a ratio of 1:4:20 for nitrogen, oxygen, and carbon dioxide, respectively. It also prevents more oxygen from entering. When food oxidises in the presence of light, it becomes discoloured and turns rancid. The taste and odour become unpleasant. There is loss of nutrients and vitamins. More importantly, there is the danger that microorganisms could proliferate, leading to contamination.
So, have we summed up the functions that these protective barriers serve? To wrap it all up, food packaging is important to us because it helps maintain the taste of food, prolong its shelf life, and ensure its quality from production to consumption.