Food tests Flashcards
(12 cards)
How do you prepare a food sample?
1) Break up food with pestle and mortar
2) Transfer food to a beaker and add distilled water
3) Stir with glass rod (to dissolve food)
4) Filter solution
What is the test for reducing sugars (glucose) called?
Benedict’s test
Describe the bendedict’s test
1) Prepare 5cm³ of food sample in test tube
2) Prepare 75°C water bath
3) Add benedicts solution to test tube (a few drops)
4) Place test tube in water bath (point it away from u)
5) Colour change
What are the colours in the benedict’s test?
Blue - No
Green - Low
Yellow - Low
Brick-red - High
What is the test for starch?
Iodine solution
Describe the starch test
1) 5cm³ of sample in test tube
2) Add a few drops of iodine
3) Colour change
What is the colour change in starch test
Iodine start browny-orange
browny-orange - no starch
blue-black - starch
What is the test for proteins?
Biuret test
Describe the biuret test
1) 2cm³ of food sample in test tube
2) 2cm³ of biuret solution (gently shake)
3) Colour change
Colour change biuret test
Blue - None
Pink/Purple - Protein
What is the test for lipids?
Sudan III
Describe Sudan III test
do this
