Food Tests - Starch And Sugars Flashcards
1
Q
Explain the process for test for starch
A
- Test solution in test tube
- Iodine in potassium iodide solution
- Gently mix by swirling
2
Q
What is the positive result for the starch test?
A
Browny orange to blue-black
3
Q
Explain the test for reducing sugars
A
- Test solution in boiling tube
- Equal volume of Benedict’s reagent
- Heat for 5 mins
4
Q
What is the positive result for reducing sugars?
A
Blue to orangey red
5
Q
Explain the test for non reducing sugars
A
- Test solution in boiling tube
- Equal volume of Benedict’s reagent
- Heat mixture
- Record colour - not a reducing sugar if remains blue
- Test solution in boiling tube
- Add hydrochloric acid
- Heat
- Sodium hydroxide to neutralise
- Add Benedict’s reagent
- Heat for 5 mins
6
Q
What is the positive result for non reducing sugar test?
A
Blue to orangey red