REAGENT TESTS OF KNOWN SUBSTANCESFood Substance Reagent Test Results

Gelatin Biuret Solution LavenderGlucose Benedict’s Solution Yellow BrownStarch Lugol’s iodine Solution Dark Blue/PurpleSodium Chloride Silver nitrate Solution (1%) White/ cloudy

ANALYSIS OF COMPOUNDS IN COMMON FOODSubstance Protein Glucose Starch Sodium Chloride

EGGPrediction + - - +

Results + - - +

PotatoPrediction + - + -

Results + + + -

SaucePrediction + - - +

Results - + + +

CarrotPrediction + + + +

Results - + + +

BananaPrediction + - - +

Results + - + -

SalsaPrediction - + + -

Results + - + +

LiverPrediction + + + +

Results - + - -

LemonPrediction + + - -

Results - + - +

CranberryPrediction + - - -

Results - + - -

ApplePrediction + + - -

Results + + + -

Kidney BeansPrediction + - - -

Results - + + +

Antiporda 1Angelica AntipordaMs. DelongH Bio Period 97 November 2005

Title: Compounds of Living Things

Objective: To determine whether or not each of the following: Protein, Glucose, Starch, Sodium Chloride are present in various food.

Hypothesis: Protein will be present in all food. Starch will be present in only Potato, Carrot, Salsa, and Liver. Glucose will be present in Carrot, salsa, and Lemon. Sodium Chloride will be present in all food except Cranberry, apple, and kidney beans.

Materials:

Safety Goggles Lap Apron 25-mL beaker 10 mL Graduated Cylinder Test Tubes Test-tube clamp/tong Test-tube rack Pipette Pi-pump Hot plate Benedict’s Solution in dropping bottle Biuret Solution in dropping bottle Lugol’s iodine solution in dropping bottle Silver nitrate solution (1 %) in dropping bottle Food assigned by teacher

Procedure:

1) Safety: Put on safety goggles, lab apron and follow necessary lab safety precautions.

2) Copy table 1B.1: Reagent tests of known Food substances. (Copy table on projector) Fill it out according to the observations you make as the teacher demonstrates

3) Copy Table 1B.2: Analysis of Compounds in Common Food (or the table on projector). Fill out your prediction for each food and substance using a plus sign (+) for present and a negative sign (-) for negative.

4) Protein test: Place 5 mL of assigned food in a test tube. Add 10 drops of Biuret solution. Compare the results (color) to the information you have copied down on

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the Reagent test of Known Food substances chart. Record the results on the Analysis of Compounds in common food chart, using a plus or negative sign.

5) Glucose Test: Add 3 mL of Benedict’s solution to 5 mL of the assigned food. Place test tube in a beaker of boiling water, and heat for 5 minutes. Compare the results (color) to the information you have copied down on the Reagent test of Known Food substances chart. Record the results on the Analysis of Compounds in common food chart, using a plus or negative sign.

6) Starch Test: Add 5 drops of Lugol’s iodine solution to 5mL of assigned food. Compare the results (color) to the information you have copied down on the Reagent test of Known Food substances chart. Record the results on the Analysis of Compounds in common food chart, using a plus or negative sign.

7) Chloride Test: Add 5 drops of silver nitrate solution to 5 mL of assigned food. Compare the results (color) to the information you have copied down on the Reagent test of Known Food substances chart. Record the results on the Analysis of Compounds in common food chart, using a plus or negative sign.

8) Copy and fill out the results your other classmates got from their experiment for the food assigned to them

9) Clean lab station. 10) Wash your hands thoroughly before living lab.

Data: see attached

Analysis:

I predicted that Protein would be present with all of the food. However, the results in this experiment proved me wrong. For instance, according to the results Liver does not have Protein present in it. That also goes for cranberry, carrot, lemon, apple and Kidney beans. I had the notion that food such as apples it being a fruit would have protein. I was rather surprised that the carrot was absent of Protein. I predicted that Potato would be the only food that would have Starch present in it. However, results show that the carrot, apple, and Kidney Beans have starch in them. I was correct about my prediction that Potato would have starch in it. I guessed that Glucose would be present in Carrot, salsa, and Lemon. I was correct to say that Glucose would be present in Carrot and Lemon. I made a conjecture that Sodium Chloride would be present in all food except Cranberry, apple, and kidney beans. I was correct that Cranberry and apple would not have Sodium Chloride present in it. I was, however, mistaken about Kidney beans not having Sodium Chloride present for it is.

I was correct about my prediction that the egg, potato, banana, and apple would have positive results for Protein. My prediction that the egg and banana would not

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have Glucose and that Liver, lemon, and apple would was correct. For starch I predicted that egg, lemon, and cranberry would be negative and that potato, carrot, and salsa would have Starch and I was also correct. I was correct to guess that the egg, potato. Sauce, and carrot would result as positive and that Cranberry and apple would be negative.

According to the results listed on the chart (Analysis of Compounds in Common Food) there was no food that contained all the compounds that were tested.

On the basis of the tests the egg, potato, banana and apple could be used as a source of Protein. The potato, sauce, liver, lemon, cranberry, apple, and Kidney beans could be used as a source of Glucose. The potato, carrot, banana, salsa, apple, and Kidney beans could be used as a source of Starch. The egg, sauce, carrot, salsa, lemon, and kidney beans could be used as a source of Sodium Chloride.

I really don’t think that the original colors of the test materials could affect the results. I do think that it may be a bit harder to determine the result because of the hue and color scheme that the original color might affect. I think that in testing for something like Glucose and Starch the color would make a difference, but the results wouldn’t change because of the color range.