The plastic revolution in food packaging began in 1960s. The reason why the choice of plastic, because it is lighter than glass, stronger than paper, but also relatively cheap. As long as we can contact the food will be able to see the figure of plastic packaging. Plastic packaging can become an integral part of the food system, because the plastic material density is small, light, transparent or opaque, easy to process as long as the replacement of the mold to obtain the containers of different varieties to the formation of mass production. But it also has many disadvantages such as: plastic deformation under high temperature and low surface hardness is easy to wear; will become brittle in the light degradation of oxygen and heat oxygen; poor conductivity, easy to produce static electricity accumulation and pollution links etc.. But in spite of this, it has brought great convenience to our life. But Brody also points out that the plastic is not there. We are in contact with many of the packaging bags, are made from different types of food packaging plastic.
We can see all kinds of plastic packaging in the form of life, there are several common:
1 bags of potato chips
Its main component is a plastic called oriented polypropylene. Brody explains: it's a good damp proof layer. In the packaging of potato chips, moisture is very critical, because the chips absorb moisture will begin to deteriorate. Wet answer of potato chips is no one likes. In order to further strengthen, many bags of potato chips are still in the inner layer of a thin layer of aluminum. The product name and nutrition information are printed on the outer layer, and a layer of polyethylene is sandwiched between the two layers of the inner and the outer layer. Brody also revealed that in the packaging bag before sealing, most companies will inject nitrogen. This prevents the chips from crushing. Oxygen will make the fat oxidation, chips produced in the smell of nitrogen would not cause any damage to the taste of chemical reaction. Food companies often spend a lot of time designing packaging, the purpose is best to save every product they sell. This is also the practice of the army. Prior to this report, the army has used a packaging to extend the shelf life of the sandwich to two years.
2 salad packing bag
Like a bag of chips, Vegetable Salad bag that is made of polypropylene with instant, and also injected a pack of nitrogen. And chips is different, is a little salad leaves need to breathe oxygen, which is why the bag with a small hole in the salad. Brody pointed out: the small hole makes the oxygen to enter, carbon dioxide can be discharged. He added that the inside of these bags often has a thin layer of anti fog layer, so that it will not happen condensation, but also allows consumers to see the beautiful green leaves.