oxidation of food Flashcards
in terms of carbon compounds, what is oxidation ?
an increase in the oxygen to hydrogen ratio (gain of oxygen or loss of hydrogen)
in terms of carbon compounds, what is reduction?
a decrease in the oxygen to hydrogen ratio (addition of hydrogen or loss of oxygen)
what happens to primary alcohols when they are oxidised by copper oxide or acidified potassium dichromate?
they turn into aldehydes (c double bond o, one more oxygen, carbonyl group) and then into carboxylic acids (cooh, also one more oxygen)
what happens to acidified potassium dichromate when it oxidises a primary or secondary alcohol?
turns from orange to green.
what happens to secondary alcohols when they are oxidised by copper oxide or acidified potassium dichromate
they turn into ketones (c double bond o, or, carbonyl group)
what happens during the oxidation of a primary or secondary alcohol by copper oxide?
the colour of the copper oxide goes from black to orange.
how to name an aldehyde ?
ends in al. e.g, propanal
what happens during the three reactions in which an aldehyde is oxidised?
- turns fehlings solution from blue to forming a brick red precipitate.
- turns acidified potassium dichromate from orange to green
- turns tollents reagent from clear to a silver mirror
what are aldehydes used as?
flavour or aroma molecules
what causes a rancid smell in food?
the oxidation of edible oils
what are antioxidants
substances that prevent oxidation of unwanted substances by being easily oxidised themselves, in place of the compounds they have been added to protect.
how to tell what is the anti oxidant in a redox ?
it will always be the substance being oxidised.
