organisation: required practical

Question 1

how to test for starch

Answer 1

1. put 2cm3 of food solution into test tube
2. add few drops of iodine which is orange
3. if starch is present it will turn blue- black . if not present it’ll stay orange

Question 2

how to test for sugars e.g glucose

Answer 2

1. add 2cm3 of food solution
2. add 10 drops of benedicts solution which is blue
3. place test tube into a beaker and half fill it will boiled water from kettle
4. leave for around 5 mins
5. if glucose present it will either be green (not much), yellow, brick red (a lot)

Question 3

how to test for protein

Answer 3

1. add 2cm3 of food solution to test tube
2. add 2cm3 of biuret solution
3. if protein present it turns from blue to purple / lilac colour

Question 4

how to test for lipids / fats

Answer 4

1. grind food with distilled water using water and pestle
2. add food solution to test tube
3. add few drops of distilled ater and ethanol
4. gently shake it
5. if lipids present a white cloudy top is formed