Oxidation of Food Flashcards
what molecules are likely to be volatile
GFM lower than 300
trend in volatility with gfm
lower gfm - more volatile
if molecule contains c and h atoms
likely to be nonpolar - fat/oil soluble
if molecule contains o and n atoms
likely to be polar - water soluble
what is the polarity of a long hydrocarbon chain with a single polar group
nonpolar
Aldehyde/ketone functional group and name
C=O
Carbonyl
Where is carbonyl aldehyde
beginning of C chain
Where is carbonyl ketone
never on the end of C chain
Names for aldehydes
end in al - methanal
Names for ketones
end in one - pentan-2-one
Formula for ketones and aldehydes
CnH2nO
How do you know if carbon compounds are oxidised
Oxygen atoms increase
Hydrogen atoms decrease
2 mild oxidising agents
-Hot copper (II) oxide
-acidified potassium dichromate
Stages of primary alcohol oxidation
- aldehydes
- carboxylic acids
Stages of secondary alcohol oxidation
- Ketones
Using mild oxidation agents, what alcohols cant be oxidised
Tertiary
Oxidation process - O:H ratio
O increases
H decreases
Can ketones be oxidised
No
3 oxidising agents to oxidise aldehydes
acidified potassium dichromate
benedicts solution
tollens reagent
colour change acidified potassium dichromate
orange - green
colour change benedicts solution
blue - cloudy red
colour change tollens reagent
silver mirror
what causes oxidation of food
oxygen
3 compounds for flavour molecules
alcohols, esters and aldehydes
Define antioxidants
Will prevent oxidation as they are reducing agents
4 examples of antioxidant
absorbic acid (vitamin C)
melatonin
tocopherol
carotene
Define free radicals
Reactive atoms or molecules with an unpaired electron
What does too many free radicals mean
attacks cell membranes which causes cell and tissue damage
what do antioxidants do (free radicals)
mop them up
what 3 compounds only form h bonds with water and not themselves
carbonyl
aldehyde
ester
