Like it or not, plastic bags have become an integral part of the food system.We throw away the outer layer of plastic packaging right after we buy our salads, sandwiches, and chips, which is wasteful; however, it’s the same layer of plastic that keeps a lot of our food fresh in transit, and We never get into this.Many plastic packaging allows us to eat on the go, or taste the perishable cookies and fish from the other side of the world, and there is a lot of scientific principles and inventions behind them.Alan·Brody (Aaron Brody), a food packaging consultant and associate professor of food science at the University of Georgia, according to which the plastic revolution in food packaging began with1960Era. So plastic is chosen because it is lighter than glass, stronger than paper, and less expensive.But Brody also pointed out:”There is no one-size-fits-all plastic”. Many of the bags we come into contact with are a combination of different types of food packaging plastics.potato chips packaging bagTake the potato chip packaging bag as an example, its main ingredient is a”Oriented polypropylene”(polypropylene oriented) of plastic. Brody explained:”That’s a good moisture barrier.”In the packaging of potato chips, moisture resistance is very important.”Because potato chips absorb water vapor, they will start to spoil. wet potatoMovies are not liked by anyone.”For added reinforcement, many potato chip bags also have a thin layer of aluminum added to the inner layer.The product name and nutritional information are printed on the outer layer, and a layer of polyethylene (the material used to make plastic shopping bags) is sandwiched between the inner and outer layers.Brody also revealed that most companies inject nitrogen into the bags before they are sealed.”This will keep the chips from crushing.”Oxygen oxidizes the fats in potato chips and produces a strange taste, but nitrogen does not cause any chemical reactions that destroy the taste.Brody also said that food companies often spend a lot of time designing packaging to best preserve every product they sell. This is also the way the military does. In previous reports, the Army used a package to extend the freshness of the sandwiches to two yearssalad bagLike the potato chip bags, the ready-to-eat green salad bags are also made of polypropylene and are also filled with a packet of nitrogen. Unlike potato chips, salad leaves need to breathe a little oxygen, which is why there are holes in the salad bag. Brody pointed out:”The pores allow oxygen to get in and carbon dioxide to get out. “These bags often also have a thin anti-fog layer on the inside, he added.”This prevents condensation and allows consumers to see beautiful green leaves. “ice cream bucketWhen making many plastic packaging, manufacturers worry not only how to keep air out, but also how to keep water vapour inside. For example, Brody said, this is very important in the packaging of ice cream. A tub of ice cream must open and close easily, but it must also have a tight seal that locks in the moisture and keeps it smooth.Stored in the refrigerator, sublimation sometimes occurs, which is the phenomenon in which water directly changes from a solid state to a gaseous state.”Once the sublimated moisture is lost, it cannot be recovered, and ice cream will sand and clump if it loses moisture.”Brody said.He also pointed out that this is why a layer of polyethylene is added to the paper tubs that hold the ice cream. And the advanced ice cream bucket is made of thick and sturdy material.Of course, as food expert Herbert·Stone (Herbert Stone), even after all the research and development, most plastic packaging still cannot preserve food in extreme environments. Stone is a food industry consultant and past president of the Institute of Food Technicians.Stone pointed out:”When food companies use plastic containers, they must ensure that they do not alter the taste of the food.”Plastic is not an inert material, it can react with other chemicals, he added. And unlike many glass or metal products, it also allows air to pass through.Water bottleHave you ever left a plastic water bottle in a hot car for too long? Then it probably tasted weird. But the reason is different than you might think: It’s not because the chemicals in the plastic seep into the water.Small amounts of air can penetrate the plastic, Stone explained, and when the temperature rises, so does the movement of the air. Heat also speeds up chemical reactions. When the chemicals in the bottle react with each other or with the substances in the external environment, the water in the bottle will taste strange.Leave a bottle of soda in a hot car and the carbonic acid will quickly escape from the bottle.”All that’s left is the soda without the bubbles.”Stone said,”Plastic is convenient, but it’s not everything. “In addition to its technical limitations, all the plastic packaging we use today generates a lot of waste. just2012years, the United States produced1400Thousands of tons of plastic waste used to be bags and containers. Plastics do not biodegrade easily, so they sometimes enter the ocean, which not only harms marine life, but even contaminates seafood.While many types of plastic are already recyclable, bright packaging that contains multiple layers of plastic is difficult to recycle because different types of plastic are handled separately in recycling bins.But Stone says we’re also getting better at making plastics that are both convenient and environmentally friendly. We’re even trying to convert waste like whey protein into plastic.
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