Food tests

Question 1

Describe the protein test

Answer 1

• Biuret test
• add biuret reagent
• if colour changes from blue to purple protein is present

Question 2

What is the test for starch

Answer 2

• iodine test
• goes from orangey brown to bluey black

Question 3

What is the test for lipids

Answer 3

• emulsion test
• add ethanol
• pour an equal amount of water to solution
• a white emulsion forms if lipid present

Question 4

How do you test for reducing sugars

Answer 4

• add beneedicts to a sample ad boil
• if potisitve colour changes from blue to brick red

Question 5

Describe the test for non reducing sugars

Answer 5

• add dilute HCL and boil
• neutralise with ssodium hydrogen carbonate
• add benedicts reagant and boil
• if positive change from blue to brick red

Question 6

How can you test for glucose specifically

Answer 6

• dip pad of glucose test strip for the sample
• colour change if glucose present
• concentration found by comparing colour to a colour standard change