Food tests term 2 practical

Question 1

reducing sugar test + outcome + specific test name

Answer 1

benedict’s test

1. Add 2 cm³ of the food sample (in solution form) into a test tube.

2, Add 2 cm³ of Benedict’s solution to the food sample

3. Shake the micture and place test tube in a boiling water bath for 2–3 minutes.
4. Record my observations
   Positive result:
   Blue → Green → Yellow → Brick-red precipitate (large amt of reducing sugar)

Question 2

starch test + outcone + specific test name

Answer 2

Iodide test
1. Place 2 cm³ of the food sample in a test tube or spotting tile.

2. Add a few drops of iodine solution (yellow-brown in color).
3. Record my observations
   Positive result:
   Yellow-brown → Blue-black (indicates presence of starch)

Question 3

lipids test + outcone + specific test name

Answer 3

(Emulsion Test)

1. Add 2 cm³ of ethanol to a drop of liquid sample in a test tube.
2. Shake the micture thoroughly.
3. Add 2 cm³ of water to mixture, shake again.

OR
1. crushed solid sample using mortar and pestle and place pieces in a test tube
2. add 2 cm³ of ethanol and shake thouroughly
3. allow particles yp settle before carefully decanting the ethanpl into another test tibe containing 2cm3 of water and shake mixture.

4. Record observation

Positive result:
Clear → Cloudy white emulsion (milky appearance indicates lipids present)

Question 4

protein test + outcone + specific test name

Answer 4

(Biuret Test)

1. Add 2 cm³ of the food sample into a test tube.
2. Add an equal volume of biurest solution
3. Shake well and allow mixture to stand for 5min.

Positive result:
Blue → violet (indicates presence of protein)