1. Organic Compounds in Food Lab

2. Purpose: Test samples of food for the presence of organic molecules using 4 indicators.

3. Procedure:
Materials: 7 food sources, beakers, pipettes, and 4 indicators:
Benedict’s Solution – detects glucose (simple sugar)
Lugol’s Iodine Solution – detects Starch (complex sugar)
Biuret Solution – detects proteins
Sudan IV – detects lipids (fats)
Procedures: At lab station

4. Procedures – At lab station
1. Demo standards and record results in Data Table 1.
2. Make predictions.
3. Place approximately 5 mL of the first food substance in each of the 4 test tubes.
Conduct the 4 indicator tests as shown in the demo:
5 drops of each substance. Benedicts – hot water 5 min
Record your results in Data Table 2.
Wash 4 test tubes and repeat with sample 2.
Repeat the above steps for all 7 substances.

5. Data Table 1: Standards Test
Substance
Glucose
Lipid
Starch
Protein
Indicator Used
Color changes from _____ to _______
Other Observation

6. Data Table 2: Organic Compounds in Food
Lipid Test
Carbohydrate Test
Protein Test
Sudan IV Color
Lipids Present
Iodine Color
Starches Present
Benedict Color
Glucose Present
Biuret Color
Proteins Present
Honey
Egg White
Potato
Milk
Apple Juice
Veg. Oil
Corn

7. Conclusion
1 to 2 paragraphs. Written in 3rd person (command) form, not in 1st person.
Discuss your Results:
Which substances contain lipids, simple sugars, starch, lipids and proteins?
How was this determined? Describe the 4 tests and the qualitative results.
Discuss any surprising or expected results. Review your original predictions.

8. Procedures
1. Place approximately 5 mL of the first food substance in each of the 4 test tubes.
2. Conduct the 4 indicator tests as shown in the demo:
5 drops of each substance.
Benedicts should sit in water bath for 5 min.
3. Record your results in Data Table 2.
4. Wash 4 test tubes in the sink and repeat with the remaining 6 samples.