Jotter 3 Flashcards
What is a condensation polymer?
A polymer whose polymerisation involves a condensation reaction.
What can be done to condensation polymers to get their monomers?
They can be hydrolysed meaning their reaction can be reversed.
How does the hydrolysis of proteins occur?
Hydrolysis of proteins is conducted in a lab by heating with a fairly concentrated hydrochloride acid under reflux.
What forces are proteins held by to be able to maintain their shapes?
Intermolecular forces (hydrogen bonding).
What do enzyme name usually end in?
-ase.
What happens to peptide links when tissue is heated up?
The peptide links remain intact although the shape of the enzyme molecule becomes irreversibly denatured.
What might some foods contain that puts them at the greatest risk of oxidation?
Fats or oils.
What must be added to foods even if they contain the smallest bit of oil or fat?
Antioxidants.
Where are antioxidants commonly used?
They are commonly used in products like, vegetable oil, animal fat, meat, fish, poultry, dairy products, mayonnaise, potato products, etc.
What methods do food manufacturers use to prevent oxidation?
Packaging the foods in an atmosphere of nitrogen or adding an antioxidant such as Vitamin C.
What happens to fats when they react with oxygen?
The fats are being broken down which causes, loss of colour, loss of nutritional value, deterioration of flavour and even a health risk due to toxic oxidation products.
What chemicals are produced when fat reacts with oxygen?
Chemicals called peroxides are produced which causes the flavour and smell to deteriorate which means peroxides are what give meat that rancid smell and flavour.
What do antioxidants do?
They prevent the formation of peroxides meaning they slow down the process of food going off.
What can oxidation reactions produce?
Free radicals.
What is a free radical?
It is a highly reactive species that contains an unpaired electron.
How do free radicals damage food?
They damage food by the removal of an electron.
How do antioxidants act on free radicals?
They act by transferring one of their electrons to the free radical which neutralises it by forming a stable pair of electrons within the free radical.
What happens to the antioxidants when they give away one of their electrons?
They turn into a stable species of free radical.
What can Vitamin C (ascorbic acid) act as?
It can can act as a reducing agent which prevents oxidation.
What does Melatonin do as a hormone?
It regulates sleep in our bodies.
What are some examples of antioxidants?
Melatonin, regulates sleep
Vitamin C, found in nuts
α-tocopherol (Vitamin E), found in nuts
β-carotene (Vitamin A), found in carrots, can improve tan
What are many of the flavour and aroma molecules?
They are aldehydes which can be oxidised.
What molecules contribute to flavour?
Molecules which are volatile.
What are some of the properties of volatile molecules?
They have low molecular mass- less than 300 (low boiling point)
They have London dispersion forces as their intermolecular force making them have a low boiling point
How can the volatility and boiling point of a compound be predicted?
The presence of O-H or N-H bonds that will cause hydrogen bonding and will make it soluble in water (polar)
The arrangement of polar covalent bonds which can result in dipole:dipole forces which increases boiling point meaning it affects volatility
Molecular size, which may affect the size of LDFs increasing the boiling point (affecting volatility)
The polarities of the solute and the solvent which affects solubility
What is the most important feature in cooking food?
Whether the functional groups that are present are water soluble or not as if they are it means they can form hydrogen bonding with water but if they can’t that means they are oil soluble (like dissolves like).
What is an important feature of cooking that involves the method and time?
Method and times are important in cooking food as if done right it preserves the flavour as some flavour molecule might dissolve in the cooking liquid and lost if done wrong.
How is flavour in food preserved when using water?
Water is used to cook foods which contain oil soluble flavours such as, green beans or broccoli.
