Reducing and Non-Reducing Sugars Flashcards
Hydrolysis reaction:
Breaks chemical bond between monomers using a water molecule
Hydrolysis breaks…
Polymers apart
How can carbohydrates be broken down into their constituent monosaccharides?
Hydrolysis reactions
Sugar is a general term for…
Monosaccharides and disaccharides
How can all sugars be classified as?
Reducing and non-reducing
Benedict’s test for reducing sugars:
Add Benedict’s reagant to a sample
Heat it in a water bath that’s been brough to the boil
If test’s positive it will form a coloured precipitate
What do reducing sugars include?
All monosaccharides and some disaccharides (e.g. maltose and lactose)
What colour is Benedict’s reagant?
Blue
Solid precipitate:
Solid particles suspended in the solution
Colour of the precipitate changes from…
Blue Green Yellow Red Brick red
Higher the concentration of reducing sugars…
The further the colour change goes
Can be used to compare the amount of reducing sugars in different solutions
What’s a more accurate way of testing for reducing sugars?
Filter the solution and weigh the precipitate
How much Benedict’s reagant should you always use?
An excess- makes sure that all the sugar reacts
Benedict’s test for non-reducing sugars:
Get a new sample of the test solution
Add dilute hydrochloric acid and carefully heat it in a water bath that’s been brought to the boil
Neutralise solution with sodium hydrogencarbonate
Carry out Benedict’s test as you would for a reducing sugar
If test’s positive it will form a coloured precipitate
If test’s negative the solution will stay blue- doesn’t contain any sugar (either reducing or non-reducing)
If the result of the reducing sugars test is negative…
There could still be a non-reducing sugar present
