Food tests Flashcards
What is the indicator for the starch test?
Iodine solution
What is the colour of the indicator?
Brown
What happens when a positive test occurs with iodine solution?
+
Nutrient present
Brown to blue-black
What happens when a negative test occurs for iodine solution?
-
Nutrient is absence
Colour remain the same
What is the indicator for proteins?
Biuret solution
What is the colour of biuret solution?
Blue
What happens when a positive test occurs with biuret solution?
+
Nutrient is present
Blue to liliac/violet
What happens when a negative test occurs with biuret solution?
-
Nutrient is absent
Colour remains unchanged which is bright blue
What is the indicator for lipid emulsion test?
Ethanol/alcohol
What is the colour of ethanol?
It is colourless
What happens when a positive test occurs with ethanol?
+
Nutrient is present
Clear solution to milky emulsion
What happens when a negative test occurs with iodine solution?
-
Nutrient is absent
Colour remains unchanged
It is colourless
