1 / 21

Investigating Organic Compounds in Foods

Explore lipids, carbohydrates, proteins, and nucleic acids in foods using indicators. Conduct tests to identify the presence of these compounds. Conduct a lab experiment utilizing various food samples and indicators such as Iodine, Benedicts, and Biuret to detect different organic compounds. Develop hypotheses and analyze results to understand the composition of foods. Optimize your experiment techniques for accurate testing.

leclair
Download Presentation

Investigating Organic Compounds in Foods

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cornell notes pg 17 in your INB Chemistry of LifeThe Essential Ingredients for Life

  2. Ingredients for Life Water Carbohydrates Lipids Proteins Nucleic Acids

  3. Properties of water Living organisms are made mostly of water Adhesive (adhere to other surfaces) Cohesive (adhere to each other) The universal solvent Why does water have these special properties???

  4. …because water is POLAR! Polar molecules have an uneven charges.

  5. glucose glucose glucose glucose starch glucose glucose glucose glucose glucose Carbohydrate (make sure to illustrate and label figures) • Store short term energy • Simple sugar (monosaccharide) – glucose • Complex sugar (polysaccharide) - starch

  6. Lipids insoluble (do not dissolve) in water “stores the most energy” Ex: 1. Fats 2. Oils 3. Cholesterol Some functions of lipids: 1. Long term energy storage 2. Insulation 3. Major component of membranes (phospholipids)

  7. Proteins Amino acids (20 different kinds) Amino Acids bonded together form a chain called a polypeptide chain. A polypeptide chain folds into a protein. Some functions of proteins: 1. Transport: hemoglobin in red blood cells 2. Movement: muscles 3. Structural: membranes, hair, nails 4. Enzymes: cellular reactions

  8. Nucleic acids Two types: a. DNA (deoxyribonucleic acid)- genetic material b. RNA (ribonucleic acid)-copy of genetic material Nucleic acids are composed of long chains of nucleotides

  9. Identifying Organic Compounds Lab

  10. PRE-LAB QUESTIONS • How do you know if a food contains protein? • How do you know if a food contains starch? • What is the difference between starch and sugar? • Why should you be careful of biuret solution? What should you do if you spill some on yourself?

  11. Introduction The most common organic compounds found in living organisms are lipids, carbohydrates, proteins, and nucleic acids. Common foods, which often consist of plant materials or substances derived from animals, are also combinations these organic compounds. Substances called indicatorscan be used to test for the presence of organic compounds. An indicator is a substance that changes color in the presence of a particular compound. In this investigation, you will use several indicators to test for the presence of lipids, carbohydrates and proteins in various foods.

  12. Title: Problem: Hypothesis: Independent variable: Dependent variable: Control: Constants: Repeated # of trials: The effect of _______ on _____. Using the indicators (listed below) which test for specific compounds. Which of the 4 major types of organic compounds are found in spinach? *Iodine change color if *Benedicts present in a *Biuret particular compound If…then…because…… Complete the rest of your Lab-write up on your own.

  13. Independent variable: Dependent variable: Control: Contants: # of Trials: The indicators added to the samples: - Iodine - Benedicts - Biuret The color change of the samples. The color of the samples before adding indicator Materials, amounts, equipment 1 for each indicator

  14. Data chart

  15. Materials 8 Test tubes Test tube holder Test tube rack Hot plate Brown paper towel Labeling tape For each organic compound test you need: 5 drops egg white 5 drops apple juice 5 drops corn oil 5 drops fish 5 drops of distilled water 5 drops butter 5 drops of potato 5 drops of spinach Starch test: Iodine solution Sugar test: Benedicts solution Protein: Biuret solution

  16. Lipid Test 1. Divide a piece of brown paper towel into 8 equal sections. In each section, write the name of one test substances, as shown. 2. In each section, place a small drop of the identified food onto the brown paper towel. With another paper towel, wipe off any excess pieces of food that may stick to the paper. Set aside for 10-15 minutes 3. Hold paper to light or window. If food sample produces a translucent or see-through spot, there is a presence of a LIPID.

  17. Carbohydrate Test - Starch 1. Label test tubes: distilled water, egg, oil, butter, apple juice, potato, spinach, fish 2. Add 5 drops of each food sample to its proper test tube. 3.Add 2-3 drops of iodine solution to each test tube and shake. *Iodine will change color fromyellow brown→blue blackin presence of STARCH. 4. Record data on table. 5. Wash test tubes thoroughly!

  18. Carbohydrate Test - Sugar 1. Set up hot water bath: Fill half the beaker with tap water and heat to a gentle boil. 2. While water bath is heating, fill each cleaned test tube with 5 full drops of the appropriate food sample. 3. Add 2-3 drops of Benedicts solution and shake. 4. Place test tubes in hot water bath and heat for 3-5 minutes. 5. Caution: Remove test tubes from water bath with test tube holder! *When heated, Benedicts solution will change colorfrom blue→green, yellow, orange, or redin the presence of SUGAR. 6. Record any color changes on data table. 7. Wash test tubes thoroughly!

  19. Protein Test 1. Put 5 drops of appropriate food samples in each labeled test tube. 2. Add 2-3 drops of Biuret solution to each test tube and gently shake. Caution: Biuret contains NaOH, a strong base. If you splash any on yourself, wash with water and notify your teacher immediately! *Biuret changes color fromlight blue→blue-violet in the presence of PROTEIN. 3. Record any color change on data table. 4. Wash test tubes thoroughly!

  20. POST LAB QUESTIONS • Which foods come from plants? What biomolecule is most common in these foods? • Which foods come from animals? What biomolecule is most common in these foods? • Does water contain any of the macromolecules that you tested for? Explain why water is used as a control.

  21. Fill out the following table by listing the foods that you tested.

More Related