Testing for Carbohydrates

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  • Created by: Mary_07
  • Created on: 08-11-17 10:52
What is the test for a reducing sugar?
Add about 5cm3 of Benedict’s reagent to a small amount of sample in a test tube. Stand the test tube in boiling water for 5 mins. A colour change from blue through green to yellow, brown and finally to red indicates the presence of reducing sugar.
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What is the test for a non-reducing sugar?
2cm3 of dilute hydrochloric acid to a sample. Heat for 5 mins. Slowly add sodium hydrogen carbonate. Add 5cm3 of Benedict’s reagent to the test tube. Stand the test tube in boiling water for 5 mins. A colour change through green and red.
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What is the food test for starch?
Add a few drops of iodine solution to a small amount of the sample. If starch is present the colour will change from orange to blue-black.
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Recap on starch.
Plant cells, A-gluocse, amylose and amylopectin, insoluble, branched
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Recap on Cellulose
Long, straight, unbranched, hydrogen bonds, microfibrils, fibres
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Other cards in this set

Card 2

Front

What is the test for a non-reducing sugar?

Back

2cm3 of dilute hydrochloric acid to a sample. Heat for 5 mins. Slowly add sodium hydrogen carbonate. Add 5cm3 of Benedict’s reagent to the test tube. Stand the test tube in boiling water for 5 mins. A colour change through green and red.

Card 3

Front

What is the food test for starch?

Back

Preview of the front of card 3

Card 4

Front

Recap on starch.

Back

Preview of the front of card 4

Card 5

Front

Recap on Cellulose

Back

Preview of the front of card 5

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