Question

Make a model by collecting the wrappers of different food items. Enlist the ways that food is stored or packaged to prevent it oxidizing?​

Answer 1

Answer:

Plastics

Plastics are organic polymeric materials that can be molded into the desired shape. The lightness and versatility of these have been confirmed over decades in the processing and packaging of food. Plastic containers and packaging protect against the contamination of food and offer adequate mechanical strength.  Due to a lower cost and lower energy consumption during manufacturing, plastics have replaced traditional packaging materials. In addition, they are able to preserve and protect the food for longer, minimizing the use of preservatives.  In relation to the consumer, they are easy to handle and open, and offer an effective surface for printing labels or brands. However, although plastics are recyclable materials, they are pollutants.  In the plastic manufacturing process, there are many varieties of plastic resins, with the  most used being:

Polyvinyl chloride (PVC): very resistant to humidity, fats and gases

Polyethylene and its varieties (PET, HDPE, LDPE). The development of the PET range has revolutionized the packaging industry, allowing plastic to compete directly with glass bottles.  Polystyrene (PS) is the plastic of choice for thermoforming due to its strength, malleability and low cost.  Cellulose is a biodegradable substance obtained from the cell wall of many vegetables and fungi. It was the first transparent film that was used in packaging and is currently used for confectionery and pastry products, in situations where vapors need to “breathe” to avoid deforming the product  Polyamides are a type of polymer that can be found in nature such as wool, or synthetically, like nylon. They are used for boiled products in bags, frozen foods, fish, meat, vegetables and processed meat and cheese.

Metals (steel, tin, aluminum)

The main use of these metals is the preservation of canned foods and beverages. The most commonly used are tin-coated steel and aluminum cans. It is an opaque material that provides an advantage for food that is sensitive to light.  Tin cans are made of steel sheet coated with tin as a measure of protection against corrosion of steel, especially when they contain products with low pH.  Aluminum is increasingly used for canning due to its lightness, low cost and capacity to be recycled. It can be found in packaging, bottle closures and wraps and laminates. It has the same barrier properties as steel but with the advantage of being resistant to corrosion.

Aluminum foil is formed by layers of laminated aluminum. It is a highly flexible product that allows to preserve or protect food in the domestic environment. However, it is difficult to use in modern fast packaging equipment due to wrinkles, rips and marks.  Thin-walled aluminum cans are suitable for carbonated beverages, while wide-walled cans are suitable for steam sterilization. Optionally, internal lacquers can be used to avoid interaction with the product and externally to protect the ink from the labeling.