If the smell of a product can sometimes bring sensory pleasure (flowers, perfumes, chocolate, etc.), it can on the other hand make some people uncomfortable. In a cupboard or a refrigerator, the cohabitation of products can cause a mixture of smells, or even the contamination of a food by the smell of another. Therefore, the choice of an adapted packaging with good barrier properties will allow to reserve its scent to the food concerned and to avoid its propagation to the ambient atmosphere or to the neighbouring products.
Choose the right packaging material
How to protect oneself from the olfactory impact of an odorous food such as cheese, fish, animal feed, or spices?
Among the plastic films used for packaging, there are multiple varieties of materials, used in single layer, or in coextruded or laminated complexes. Each material brings its own properties of mechanical resistance, gas or water vapour tightness, sealability, or temperature and cold resistance.
As far as odorous products are concerned, the property that will be sought is the barrier to gases, which carry the volatile compounds responsible for the propagation of odors.
Which films for which barrier properties?
The most effective barrier is provided by an aluminum foil. Common examples are PET/Alu/PE or Paper/Alu/PE laminates. They preserve flavors and provide an excellent barrier to oxygen, moisture and UV.
Next are metallized films (metallized PET/PE…) and PE/EVOH/PE films, which have good gas barrier properties and still allow for vacuum bagging.
A PET/PE plastic film is less efficient, but it will still present a significant barrier to oxygen and moisture for less demanding applications.
Finally, single-material PE or PP films have a satisfactory water vapor barrier but a poor oxygen barrier.
Unfortunately, bags made from complex films are difficult to recycle with the current state of technology. There is promising research underway with chemical processes to dissolve the material, but these techniques are not yet at the industrial stage.
Preferably, we will work towards films made from a single material, or towards complex films made by assembling several layers of the same basic material, most often polyethylene, but with different properties (density, melting temperature, rigidity, etc.)
An optimal locking system
As the product is packaged in a package with sufficiently effective barrier properties, the question arises as to the choice of closure. Thanks to their hermeticity, the pouch and its closure must guarantee perfect protection of the food and an optimal barrier to odors.
To package an odorous food, different closing systems are available: sealing, folding with a sticker, simple or multi-track zipper with or without a slider, repositionable adhesive, cap, etc. Each of these systems has a different level of efficiency. Each of them has a different level of effectiveness against odors.
The conditions of consumption of the product will determine the choice of closure. If the food is consumed in its entirety upon opening, a simple seal will be sufficient. If the food is not very odorous and will be consumed in several times – for example, a packet of rice – we can move towards a closure by folding assisted by a sticker. If the food is particularly odorous, it is then essential to provide an adapted closure: cap or zip. 100% hermetic, the cap will be used for liquid or pasty products and for some powders. Single or multi-lane zippers, with or without a slider, are recommended for portionable foods, such as grated cheese, coffee or spices.
The quality of the packaging and its airtightness also contribute to the reduction of food waste. A product will be more likely to be thrown away if it smells bad in the cupboard or the refrigerator while it is still consumable, its only fault being that it releases its flavours at a time when they are not wanted.
Find all our bagging solutions! For more information, please contact us and download the Packaging Guide on the theme of Bagging.