Food Tests Flashcards
What are food tests?
A way to find out whether a food has a specific vitamin or mineral
How do you identify Glucose (Reducing sugar)?
-Add benedicts solution
-test tube of 60-70°C
-in water for 5 minutes
-After that check the colour
Blue: No glucose
Green:Very Little Reducing Sugars
Orange:Little Bit reducing Sugars
Red: 100% Reducing sugars
And if iy turns yellow there is surcose present
Food Test for starch?
-Use Iodine
-Add drops to the food sample
-If it changes from Orange-Brown to Blue Black Starch is present
Food Test For Proteins
-Add drops of biurette solution
-If protein is present then a colour change of Blue to Violet/Purple will occur
Food tests for lipids (fats)
-Food Sample is placed in **2cm³ ** of ethanol and then shaken
-After that the ethanol solution is added to an equal volume of water in r.t.p
-A positive test will show a cloudy emulion/look or have a white ring across the surface of the solution
-You could also test by wiping the food smaple onto a some blank paper then if there is fats the paper will turn translucent
Food test for vitamin C
-Add 1cm³ of DCPIP solution to a test tube
-Add a small amount of the food sample
-A positve test shows the blue colour of the dye dissapearing
What can biurete solution find?
proteins
