Oxidation of Food Flashcards
What are primary alcohols oxidised to?
Aldehydes.
What are secondary alcohols oxidised to?
Ketones.
What observation can be made from the oxidising agent copper (II) oxide?
A brown solid is formed from the black copper (II) oxide.
What observation can be made from the oxidising agent acidified potassium dichromate?
A notable change of colour from orange to green can be seen.
How are aldehydes identified?
By the CO (carbonyl group) with a hydrogen atom attached.
How are ketones identifies?
By the CO (carbonyl group) which is attached to two other carbon atoms.
What does acidified potassium dichromate do when reacted with an aldehyde?
Turn from orange to green.
What does fehling’s solution do when reacted with an aldehyde?
Turn from blue to red.
What does tollen’s reagent do when reacted with an aldehyde?
Turn from colourless to silver.
What happens when an aldehyde is oxidised?
It forms a carboxylic acid.
How does oxidation affect the oxygen to hydrogen ratio?
There is an increase.
How does reduction affect the oxygen to hydrogen ratio?
There is a decrease.
What does the polarity of a molecule indicate?
Whether they’re best cooked in water or oil, and whether valuable nutrients will be stolen from the food or if it will pass on its flavoring to the solvent.
What happens when an egg is fried?
When an egg is fried, heat causes proteins in the egg white and yolk to denature—this means the proteins unfold from their natural shapes. These unfolded proteins then bond with each other, forming a network that changes the egg from a clear, runny liquid to a firm, opaque solid.
What happens when meat is cooked?
When meat is cooked, heat denatures the proteins, causing them to unfold and coagulate, which changes the meat’s texture.
What is an antioxidant?
An antioxidant is a molecule that prevents unwanted oxidation reactions from occurring by oxidising in place of the compounds they have been added to protect.
What are some solutions that manufacturers use to prevent the spoilage of food?
Packaging in airtight containers – to limit oxygen exposure. Using vacuum sealing or inert gases – such as nitrogen to replace oxygen in packaging. Refrigeration or freezing – to slow down oxidation reactions. Using light-blocking packaging – since light can speed up oxidation.
