Chapter 3 Flashcards
How does an inner layer of aluminum foil in packages protect food?
It protects it from oxygen and moisture because it is impermeable from being penetrated by moisture or gas.
What are the advantages and disadvantages of plastic?
Advantages: easily molded into other shapes, cheap material
Disadvantages: Semi permeable and allows oxygen and moisture to enter through it in a slow rate deteriorating a product’s shelf life over time and restricting it.
What are two ways of solving the packaging waste problem?
Disposal of packages leads to the build up of landfills across the nation
- Recycling
- Expand the Single bag ban to other states (only allow use of reusable bags)
How is the RTE military pouch shape make it more effective in storing food than a can?
The thin layer of the RTE pouch allows for heat to pass through it more easily getting to the food in a quicker amount of time.
Heat takes a longer time to pass through the metal layer of a can thus giving it a greater opportunity to overheat and damage the food.
What are the purpose of additives in packaging? Ex: antioxidants
When shear stress is added to break up polyethelene plastic polymers to mold shape free radicals are produced and when combined with oxygen they produce ketones and aldehydes which lead to the production of bad smelling compounds. To prevent this from happening antioxidants are added to get rid of the free o2 in the system.
What is the preferred polymer chain of plastic?
Linear chains.
Describe the process by which plastic is made?
Crude oil is combined together in fragments to produce multiple polyethelene molecules which combine with one another and are either chemically reacted (where linear polyethylene chains cross link with one another through covalent bonding) and cooled to make thermoset gels or simply cooled to make thermoplastic gels.
Thermoplastic vs. thermoset:
Thermoplastic refers to a type of plastic that can be melted by heat, have it’s shape modified and then altered to produce a new shape. Thermoset refers to a type of plastic whose polyethylene molecules are bound together by covalent bonds and as a result are fixed in the shape that they are in and cannot be changed unless those covalent bonds are broken (how?).
