organic compounds in food lab. purpose: test samples of food for the presence of organic molecules...

Organic Compounds in Food Lab

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

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

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.

Data Table 1: Standards Test

Substance

Glucose Lipid Starch Protein

Indicator Used

Color changes

from _____ to _______

Other Observati

on

Data Table 2: Organic Compounds in Food

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

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.

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.