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Download Organic Compounds in Foods Lab What organic compounds are
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Organic Compounds in Foods Lab What organic compounds are present in the foods we eat? Background Information: Testing for Carbohydrates (Sugar & Starch) Lipids, and Proteins Simple carbohydrates are made of monomers called glucose and fructose. When these base monomers combine they form complex carbohydrates such as sucrose (table sugar) and starch. Proteins are composed of amino acids. Lipids are composed of fatty acids attached to a glycerol backbone. The chemical properties of each type of compound can be used to identify it. Step 1: Set a Standard for Comparison Before you begin to test foods, you need to set a standard for comparison. The substances you use for a standard are known to yield a positive test result for a particular type of molecule. Water is your control substance to show a negative result. Test for Simple Sugars : Benedict’s Solution Substance Monomer Type Reagent Honey Glucose Simple Sugar (Carbohydrate) Benedict’s Solution Water No Glucose inorganic Benedict’s Solution Monomer Type Reagent Glucose Starch (Carbohydrate) Lugol’s Solution No starch inorganic Lugol’s Solution Color Results Test for Starch: Lugol’s Solution Substance Corn Starch Water Color Results Test for Lipids: Brown Paper Substance Monomer Type Reagent Vegetable oil Fatty acid Lipid Brown Paper Water No lipids inorganic brown Paper Color Results Test for Protein: Biuret Substance Monomer Type Reagent Egg Albumin Amino acid Protein Biuret Water No lipids inorganic Biuret Color Results Testing for Sugar, Starch, Lipids, and Proteins Background Information Grapes are fruits that are the ripened ovary of a flowering plant. Potatoes are tubers used by plants for storage. Onions are bulbs of consecutive layers of leaf scales. Milk is produced by mammals. Corn chips are a processed food. Which of the foods contain simple sugars, starches, lipids, and proteins? Step 2: Prediction Based on your life experiences, what results do you expect for each food? (Write the predicted color.) Reagent Apple Potato Onion Milk Corn Chip Onion Milk Corn Chip Benedict’s Solution Lugol’s Solution Brown Paper Biuret Solution Step 3: Test Data (Record the actual color.) Reagent Apple Potato Benedict’s Solution Lugol’s Solution Brown Paper Biuret Solution Step 4: Test Results: Put a “+” if the food is positive for the compound and a “” if it is negative. Organic Compound Simple Sugar Starch Lipid Protein Apple Potato Onion Milk Corn Chip Food Lab Analysis: Please use complete sentences. 1. How did the actual results compare to your expected results? 2. Why didn’t we do a test for nucleic acids? 3. Why is milk the first food that mammals consume? Explain why milk does not contain starch, but does contain sugar, protein, and lipids. 4. What organic compounds would you expect to find in the following foods? hamburger meat potato chips salmon granola bar raisins chocolate 5. The cell wall in plant cells provides a layer of protection that animal cells do not have. To make up for this, animal cells have extra fats (cholesterol) to in the cell membrane. Cholesterol can build up and block arteries. What kind of diet would limit the amount of cholesterol? 6. Look at the nutrition labels below. Do they match your test results? What additional information is given? Fritos
