1.0 food tests

Question 1

what is the food test for reducing sugars

Answer 1

1. add blue Benedict’s solution
2. heat the sample to boil.

Question 2

what are the positive and negative results of the reducing sugars food tests

Answer 2

green –> yellow –> brick red
darker = more concentration
negative = stays blue

Question 3

what is the food test for non reducing sugars

Answer 3

take a new sample
1. heat new sample with dilute hydrochloric acid
2. neutralise this with sodium hydrocarbonate
3. heat sample with Benedict’s solution.

Question 4

what are the positive and negative results for non reducing sugars test

Answer 4

green –> yellow –> brick red –>
darker =. more concentration
negative = stays blue

if negative there is no reducing or non reducing sugars present.

Question 5

what is the food test for proteins

Answer 5

1. add sodium hydroxide so its alkaline
2. add copper sulphate solution

Question 6

what are the positive and negative results for protein test

Answer 6

contains protein = turns purple
no protein = stays blue

Question 7

what is the food test for starch

Answer 7

1. add iodine dissolved in potassium iodide solution

Question 8

what are the positive and negative results for starch

Answer 8

contains starch = changes from browny-orange to dark blue-black
no starch = stays browny-orange

Question 9

what is the food test for lipids

Answer 9

1. shake the test tube with ethanol for one minute
   2.pour water into the solution

Question 10

what are the positive and negative results for lipids

Answer 10

positive = milky emulsion forms
negative = no change

Question 11

what are the 4 food tests reactant to go with it

Answer 11

sugars = Benedict’s
proteins = biuret
starch = iodine
lipids = ethanol