National Chemistry Week 2000: JCE Resources in Food Chemistry

Chemical Education Today

National Chemistry Week 2000

JCE Resources in Food Chemistry

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by Erica K. Jacobsen

I faced the students with a small bag of tricks. A brandnew high school chemistry teacher with no tried and true labs. No rock ’em, sock ’em activities for the day before winter break. However, I soon found a rescuer. The Journal of Chemical Education. My monthly issue was a gold mine where I could always find a few choice nuggets for the classroom. Even now that I’ve left the classroom to work at Journal House, I find myself “mining” back issues. Often something new and “wow” jumps out. I’ve photocopied many articles to add to my bag of tricks for when I re-enter the classroom. November brings another National Chemistry Week, and this year’s theme is food chemistry. I was asked to collect and evaluate JCE resources for use with this theme, a project that took me deep into past issues of JCE and yielded many treasures. Here we present the results of searches for food chemistry information and activities. While the selected articles are mainly at the high school and college levels, there are some excellent ones for the elementary school level and some that can be adapted for younger students. The focus of all articles is on the chemistry of food itself. Activities that only use food to demonstrate a principle other than food chemistry are not included. (The

orange juice clock uses food, but it could be made with any electrolyte solution—the food itself is not necessary.) Articles that cover household products such as cleansers and pharmaceuticals are also not included, as resources on this topic are numerous enough for their own resource paper if desired. Each article has been characterized as a demonstration, experiment, calculation, activity, or informational item; several fit more than one classification. Also included is an evaluation as to which levels the article may serve. Articles that appeared adaptable to other levels, but are not designed explicitly for those levels, were labeled “possibly h.s.” “possibly elem.”, and so forth. Keywords are listed for each article but those (such as food science) that apply to all articles have not been included. Most recent articles are listed first. W

Special JCE Online Supplements

Eleven articles (resources 6, 8, 28, 33, 36, 39, 41, 42, 47, 48, and 53) are marked in bold type and carry a W. This indicates that the full text of the article is available on JCE Online. Since all references are to Journal articles, they appear in abbreviated form, including only year, volume, page.

★ I. Resources 1–5: JCE Classroom Activities 1. Colors to Dye for: Preparation of Natural Dyes. Journal Staff; 1999, 76, 1688A. Experiment; all levels Dyes; natural products Students extract colored compounds from onions and blueberries, use them to dye white cloth, and investigate ways to change the color and prevent it from washing out. Blueberries and onion 2. Soup or Salad? Investigating the skins produce natural dyes Action of Enzymes in Fruit on Gelatin. that can be used to tie dye Jacobsen, Erica; 1999, 76, 624A. cloth. Experiment; all levels Enzymes; biochemistry Students investigate the enzymatic reason for the warning on many gelatin packages “Do not use with fresh or frozen pineapple.” The effect of differently treated pineapple samples on gelatin is explored.

Enzymes in fresh pineapple break down the structure of set gelatin and leave it watery (top). Microwaved fresh pineapple does not break down the gelatin, because the microwaving denatures the enzymes.

3. Liver and Onions: DNA Extraction from Animal and Plant Tissues. Nordell, Karen J.; Jackelen, Anne-Marie L.; Condren, S. Michael; Lisensky, George C.; Ellis, Arthur B.; 1999, 76, 400A. Experiment; h.s./coll. Biochemistry; nucleic acids/DNA/RNA Students extract DNA from liver. DNA extraction can be used in conjunction with a discussion of polymers and their properties. This activity can be used to complement a diffraction experiment illustrating how the double helix structure of DNA was determined. 4. How Big Is the Balloon? Stoichiometry Using Baking Soda and Vinegar. Journal Staff; 1997, 74, 1328A. Experiment; h.s./coll. Stoichiometry; gases Students investigate stoichiometry and limiting reactants by reacting vinegar and baking soda and collecting the carbon dioxide produced in balloons. 5. Anthocyanins: A Colorful Class of Compounds. Journal Staff; 1997, 74, 1176A. Experiment; all levels Acid–base chemistry; natural products Students use pigments from items such as flower petals, juices, and cabbage leaves to investigate acid–base indicators.

Pigments from petunia petals, in solution.

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★ II. Resources 6–9: JCE Articles with Several Examples of Food Chemistry (no other keywords given) 6.W Cooking with Chemistry. Grosser, Arthur E.; 1984, 61, 362. Experiment/demonstration; all levels Includes a table of multiple cooking examples of scientific principles. For example, gases and gas laws can be related to soufflés and yeast dough. 7. Basic Concepts of Culinary Chemistry. Friedstein, Harriet G.; 1983, 60, 1037. Informational/demonstration; h.s./coll. Presents five questions concerning the chemistry of food and an answer to each. For example, one question is, “What causes the greenish color around the yolk of hard-boiled eggs?”

8.W Illustrating Chemical Concepts through Food Systems: Introductory Chemistry Experiments. Chamber, IV, E.; Setser, C. S.; 1980, 57, 312. Demonstration/experiment; all levels Describes multiple demonstrations that use foods to illustrate chemical concepts. Concepts covered include vaporization of liquids, reaction rates, adsorption, solutions, colloidal dispersions, suspensions, and pH. 9. The Home Preparation and Preservation of Food. Pfund, Marion C.; 1942, 19, 138, 244. Informational/experiment/demonstration; all levels Contains multiple examples on how chemistry is applied in the kitchen. Many could be converted into demonstrations or experiments. Page 244 contains a correction to the original article which began on page 138.

Boiling eggs for too long or too quickly can result in greenish yolks (shown on right) instead of the usual yellow color. The green is a result of the formation of iron(II) sulfide.

★ III. Resources 10–53: JCE Articles on a Single Topic 10. Gas Me Up, or, A Baking Powder Diver. Derr, Henry R.; Lewis, Tricia; Derr, Bretton J.; 2000, 77, 171. Experiment/demonstration; all levels Acid–base chemistry; gases; outreach An activity that has been used in an outreach program for a past National Chemistry Week. Participants make-and-take a diver constructed from a disposable pipet, wire, and baking powder. The diver repeatedly rises to the surface and then submerges due to the generation and release of carbon dioxide gas. 11. Science for Kids Outreach Programs: College Students Teaching Science to Elementary Students and Their Parents. Koehler, Birgit G.; Park, Lee Y.; Kaplan, Lawrence J.; 1999, 76, 1505. Experiment/demonstration; all levels Outreach; public understanding Describes a “Science for Kids” outreach program where college students lead workshops for elementary school students and their parents. One of the two topics described is “Chemistry and Cooking”. Detailed descriptions of the experiments on this topic are available as supplemental material in JCE Online at http:// jchemed.chem.wisc.edu/Journal/issues/1999/Nov/abs1505.html. 12. What Is It Used for? A Consumer–Chemical Hunt. Last, Arthur M.; 1999, 76, 1503. Hunting for Chemicals in Consumer Products. Journal Staff; 1999, 76, 1504A. Activity; h.s./coll. Public understanding; consumer chemistry Students are given clues that describe chemicals and are required to identify the chemical and find a consumer product containing

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that chemical. Many of the chemicals are found in food products. The first citation is the original article, intended for college level students. The second citation is its adaptation into a Classroom Activity, suitable for high school students. 13. Using Data Pooling to Measure the Density of Sodas: An Introductory Discovery Experiment. Herrick, Richard S.; Nestor, Lisa P.; Benedetto, David A.; 1999, 76, 1411. Experiment; h.s./coll. Consumer chemistry; solutions/solvents Students determine and compare the densities of diet and regular soda. Collected data are also used to compare the accuracy and precision of different types of volumetric glassware. Soda volumes are measured using graduated cylinders, burets, and pipets.

A visual comparison of the densities of diet and regular cola as the cans float or sink in water.




★ III. Resources 10–53: JCE Articles on a Single Topic, continued 14. Sweet Chemistry. Aurian-Blajeni, Benedict; Sam, Jonathan; Sisak, Michael; 1999, 76, 91. Experiment; h.s./coll. Spectrophotometry; dyes Students investigate food colorings and the dyes from M&M candies using a spectrophotometer. 15. The Alginate Demonstration: Polymers, Food Science, and Ion Exchange. Waldman, Amy Sue; Schechinger, Linda; Govindarajoo, Geeta; Nowick, James S.; Pignolet, Louis H.; 1998, 75, 1430. Demonstration; all levels Polymer chemistry; ion exchange Students make nontoxic strands of crosslinked calcium alginate and then break the crosslinks using brine. Alginate is used in many foods as a thickener.

19. Detection of Catalysis by Taste. Richman, Robert M.; 1998, 75, 315. Demonstration; h.s./coll./possibly elem. Catalysis; enzymes; biochemistry Students taste milk that has been treated with Lactaid, which contains the enzyme lactase, and compare it to untreated milk. The authors include an order of magnitude estimation of the average number of substrate turnovers of each lactase molecule. 20. Showing Food Foams Properties with Common Dairy Foods. Bravo-Diaz, Carlos; Gonzalez-Romero, Elisa; 1997, 74 ,1133. Experiment; h.s./coll./possibly elem. Physical chemistry; proteins/peptides Students create food foams using egg whites and investigate the effect of added ingredients on foam stability. 21. The Sweetness of Aspartame: A Biochemistry Lab for Health Science Chemistry Courses. Stein, Paul J.; 1997, 74, 1112. Experiment/demonstration; coll./possibly h.s. Proteins/peptides; biochemistry Students prepare solutions using different amounts of a commercial sweetener that contains aspartame. The solutions are used in a blind taste test to investigate the concept of saturation using the binding of the ligand aspartame to the protein receptor that determines taste.

Products that contain alginate, which can be used to demonstrate polymer chemistry. 16. Determination of Sugar Content in Commercial Beverages by Density: A Novel Experiment for General Chemistry Courses. Henderson, Susan K.; Fenn, Carol A.; Domijan, John D.; 1998, 75, 1122. Experiment; h.s./coll. Molecular properties/structure Students measure the density of solutions of known sugar concentration and use the information to determine the sugar content of commercial beverage samples. Graphing of calibration curves is required to determine the sugar concentrations of the commercial beverages. 17. Sugar Dehydration without Sulfuric Acid: No More Choking Fumes in the Classroom! Silverstein, Todd P.; Zhang, Yi; 1998, 75, 748. Demonstration; h.s./coll./possibly elem. Thermodynamics; redox reactions The authors combine the two popular demonstrations of dehydration of sucrose to form a black column of carbon and the oxidation of sugar with potassium chlorate. They eliminate the use of sulfuric acid and reduce the amount of smoke produced. 18. Why Do Alcoholic Beverages Have ‘Legs’? Silverstein, Todd P.; 1998, 75, 723. Demonstration; coll. Intermolecular forces; aqueous solution chemistry Illustrates intermolecular forces through the demonstration of how a noncarbonated alcoholic beverage in a glass has “legs” that seem to run continually up and down the inside surface of the glass.

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22. Vanillin: Synthetic Flavoring from Spent Sulfite Liquor. Hocking, Martin B.; 1997, 74, 1055. Informational; coll./possibly h.s. Organic chemistry; industrial chemistry; natural products Outlines the history of vanillin and its uses and describes the preparation of synthetic vanillin. 23. Showing Emulsion Properties with Common Dairy Foods. BravoDiaz, Carlos; Gonzalez-Romero, Elisa; 1996, 73, 844. Experiment; h.s./coll./possibly elem. Emulsions Students examine the nature and stability of food emulsions and investigate the effect of heat and additives on emulsions. 24. Improved End Point Detection in the Redox Titration of Vitamin C in Green Peppers. Deal, S. Todd; Pope, Sandi R.; 1996, 73, 547. Experiment; coll./possibly h.s. Biochemistry; vitamins Presents an improvement on the lab cited in #37 (1988, 65, 926). Using the previously described procedure, the end point was difficult to see. The authors solve the problem through filtration. 25. More Chemistry in a Soda Bottle: A Conservation of Mass Activity. Duffy, Daniel Q.; Shaw, Stephanie A.; Bare, William D.; Goldsby, Kenneth A.; 1995, 72, 734. Experiment/demonstration; h.s./coll. Conservation of mass; acid-base chemistry Students investigate the law of conservation of mass using the reaction between vinegar and baking soda. The reaction is carried out both in an open and a closed container. A mass change is detected in the open container, but not in the closed container. 26. Improving a Microscale Vitamin C Laboratory. Helser, Terry L.; 1995, 72, A10. Experiment; h.s./coll. Microscale; vitamins Presents an improvement on microscale labs that determine the




★ III. Resources 10–53: JCE Articles on a Single Topic, continued amount of vitamin C in juices through titration with 2,6dichloroindophenol. The improvement uses dye and ascorbic acid standard solutions that are more stable than previously described. 27. Determining Iron Content in Foods by Spectrophotometry. Adams, Paul E.; 1995, 72, 649. Experiment; h.s./coll. Spectrophotometry; element: iron Students determine the amount of iron in various foods through spectrophotometric analysis. The reaction used is that of the iron(III) ion and thiocyanate ion to produce a colored complex ion. 28.W Cooking Efficiencies of Pots and Pans. Selco, Jodye I.; 1994, 71, 1046. Calculation; h.s./coll. Thermodynamics; metals Describes “real life” situation heat capacity calculations using pots and pans. For example, the author calculates whether it is more efficient in time and energy to cook in a copper bottom pot instead of an all aluminum pot. 29. Quantitative Microscale Determination of Vitamin C. Kumar, Vinay; Courie, Philip; Haley, Shari; 1992, 69, A213. Experiment; h.s./coll. Microscale; vitamins Students use a microscale method to determine the amount of vitamin C in products such as orange juice, fruit drinks, and vitamin C tablets. The experiment uses an iodimetric titration that works well with the colored beverage samples. 30. The Thermodynamics of Home-Made Ice Cream. Gibbon, Donald L.; Kennedy, Keith; Reading, Nathan; Quieroz, Mardsen; 1992, 69, 658. Informational/experiment; coll./possibly h.s. Thermodynamics; colligative properties Instructional ideas using home-made ice cream. Describes three major experiments dealing with heat capacity, viscosity, and freezing point depression. Includes heat capacity problem solving.

Students gather thermodynamic data while making ice cream in a handcranked ice-cream freezer.

31. Freezing Point Depression in a Bottle of Soda. Bare, William D.; 1991, 68, 1038. Demonstration; h.s./coll. Aqueous solution chemistry; gases Carbonated seltzer water in a bottle is used to demonstrate the effect of solute concentration on the freezing point of an aqueous solution. The water is shown to have two freezing points: one before the cap is removed and one after cap removal and carbon dioxide gas release.

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32. Demonstrating What ‘Light’ Margarine Means. Glover, A. Donald; Kolb, Kenneth E.; 1991, 68, 654. Experiment/demonstration; all levels Lipids; consumer chemistry Shows the difference between regular, light, and extra light margarine to be water content. 33.W Measurement of Eggs: A General Chemistry Experiment. Newton, Thomas A.; 1990, 67, 604. Experiment; h.s./coll./possibly elem. Measurement; data analysis Students measure the mass, dimensions, and volume of an egg and its separated components. Percent composition is calculated using the data. Students are required to devise a method in advance for separating the egg components. 34. A New Approach to the Baking Soda-Vinegar Reaction. Carlson, G. Lynn; 1990, 67, 597. Demonstration; h.s./coll. Acid–base chemistry; bonding Students represent the reacting atoms in the baking soda/vinegar reaction. 35. Acid Content of Beverages: A General Chemistry Experiment Involving the Resolution of Apparent Anomalies. Fuchsman, William H.; Garg, Sandhya; 1990, 67, 67. Experiment; coll./possibly h.s. Acid–base chemistry Students measure the acidity of sour fruit beverages by pH and by titration with hydroxide ion solutions. Students are required to explain the discrepancies they obtain. The experiment connects the concepts of strong and weak acids to real life products. 36.W Quantifying a Colligative Property Associated with Making Ice Cream. Sund, Roberta; 1989, 66, 669. Experiment; h.s./coll. Colligative properties; solutions Students collect data while freezing homemade ice cream in order to quantify the effect of rock salt in depressing the freezing point of water. The author includes sample data and calculations. 37. Determination of the Effect of Various Modes of Cooking on the Vitamin C Content of a Common Food, Green Pepper: An Introductory Biochemistry Experiment. Johnson, Eric R.; 1988, 65, 926. Experiment; coll./possibly h.s. Biochemistry; vitamins Students study the effect of various modes of cooking on the vitamin C content of green pepper. Green pepper extracts are titrated with NBS solution to determine vitamin C content. 38. A Tale of Two Sweeteners. Goldsmith, Robert H.; 1987, 64, 954. Informational; h.s./coll. Organic chemistry; history Describes the discovery and properties of two synthetic sweeteners, dulcin and saccharin.


saccharin

O O

C

N− Na+

NH

C2H5O

S

O 1

C NH2

O 2

dulcin

The chemical structures of two synthetic sweeteners; saccharin, 1, is above and dulcin, 2 is below. Structures rendered by Paul F. Schatz and Randall J. Wildman, using MacSpartan software.

39.W The Rise of Self-Rising Flour: A Recipe for Success. McCamish, Malcolm; 1987, 64, 710. Informational/experiment/demonstration; h.s./coll. Gases; acid–base chemistry Explains the action of baking aerators such as baking powder. The author includes eight demonstrations/experiments, such as determination of the amount of immediately available carbon dioxide in baking powder and the detection of the flavor of various baking products on different areas of the tongue. 40. Butter and Margarine: Their Chemistry, Their Conflict. Oliver, William R.; McGill, Diana Combs; 1987, 64, 596. Informational; h.s./coll. Lipids; nutrition Presents the history, manufacture of, and dietary considerations of butter and margarine.

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★ III. Resources 10–53: JCE Articles on a Single Topic, continued 41.W Chemistry in the Dyeing of Eggs. Mebane, Robert C.; Rybolt, Thomas R.; 1987, 64, 291. Experiment; h.s./coll./possibly elem. Acid–base chemistry; dyes Describes multiple experiments that investigate factors influencing the intensity of dye that adheres to the surface of an eggshell. The authors include photographs and describe the results of changing factors such as pH, dye concentration, eggshell surface, solvent ionic strength, and the amount of acid added.

foods. Allows students to examine their own eating preferences and how to eat better for less. The authors describe the calculations and include a data and results table for over twenty foods. 47.W Ice Cream: Delicious Chemistry. Martino, James; 1983, 60, 1004. Experiment; h.s./coll./possibly elem. Bonding; solutions Uses ice cream to illustrate solution theory and the relation of physical properties to bond type. The author includes twelve questions for students to answer after making the ice cream. 48.W Soft Drink Bubbles. Cragin, James H.; 1983, 60, 71. Experiment/demonstration; all levels Gases; nucleation Students examine nucleation effects using a carbonated soft drink and ice. Compares the effervescence with ice cubes, without ice cubes, and with smooth, wet ice cubes.

The results of eggs dyed in stock dye solutions with varying pHs. In the first row, from left to right, pH increases from 1 to 6; second row, left to right, pH increases from 7 to 12. 42.W Ester, What’s in My Food? Clarke, Michele; Brown, Ann; Epp, Dianne N.; Gallup, Mary; Wilson, Jeffrey R.; Wuerthele, Judith A.; 1986, 63, 1050. Experiment/demonstration; all levels Outreach, organic chemistry, flavor A demonstration program that has been used for outreach. Deals with the concept of “Odor + Taste = Flavor” and introduces esters as some of the chemicals responsible for the flavor of food. 43. Curdling Chemistry—Coagulated Milk Products. Oberg, Craig J.; 1986, 63, 770. Informational; h.s./coll. Consumer chemistry Describes how various cheeses are made. 44. Chemical Additives in Common Table Salt. Tyler, David R.; 1985, 62, 1016. Informational; h.s./coll. Consumer chemistry Lists additives in table salt and discusses why they are present.

49. Weight-Loss Diets and the Law of Conservation of Energy. Hill, John W.; 1981, 58, 996. Calculation; h.s./coll. Nutrition Describes calculations that investigate how dieting works and the effect of exercise on weight loss using the law of conservation of energy. 50. Why Oatmeal Sticks to Your Ribs. DeLorenzo, Ronald; 1981, 58, 787. Calculation; h.s./coll. Nutrition; calorimetry Describes a calculation that supports the idea that “oatmeal sticks to your ribs”. Shows the calories necessary to raise the temperature of a bowl of cold milk (poured over cereal) to body temperature. 51. Collecting Labels for Household Products: A Project for Students in Chemistry Courses for Nonscience Majors. Melford, Sara Steck; 1975, 52, 381. Activity; h.s./coll. Consumer chemistry; nutrition Students collect food product labels and identify the chemical on the labels. The author describes using the project for foods, drugs, and cleaners.

45. Saturated and Unsaturated Fats: An Organic Chemistry Demonstration. Broniec, Rick; 1985, 62, 320. Experiment; h.s./coll. Organic chemistry; lipids Students use a permanganate test to determine if food samples contain unsaturated fats.

52. The Iron Content of Breakfast Cereals. Laswick, Patty Hall; 1973, 50, 132. Experiment; h.s./coll. Spectrophotometry; element: iron Students determine the amount of iron in commercial cereal products using an atomic absorption spectrophotometer. Helps students to realize the nutritional poorness of some products and requires them to read nutritional labels.

46. Nutrition and Problem Solving: Food for Thought. Denio, Allen A.; Bennett, Charles R.; 1984, 61, 1076. Calculation; coll./possibly h.s. Nutrition; consumer chemistry Students calculate the number of Calories per dollar of various

53.W The Story of Baking Powder. Ziegler, P. F.; 1926, 3, 492. Informational; h.s./coll. History; acid–base chemistry Describes the discovery and manufacture of baking powder and the history and chemistry of its use.

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★ IV. Resources 54–55: JCE Software Publications Acknowledgment The author thanks Nancy Gettys for beginning the groundwork for this resource paper by doing extensive searches of the JCE Online index and examining the long lists of articles that resulted.

continued from page 1264 54. The JCE CD-ROMs include all articles since September 1996. This includes 20 of the articles from this resource paper. 55. Chemistry Comes Alive! Vol. 3: Abstract of Special Issue 23 on CD-ROM. Jacobsen, Jerrold J.; Moore, John W.; 1999, 76, 1311. Demonstration; h.s./coll. Computer assisted instruction Chemistry Comes Alive! Volume 3 includes two video clips relevant to food chemistry. The first is the energy from the oxidation of food, where a Cheetos snack chip and celery are oxidized by molten potassium chlorate to compare the energy content of each. The second is the formation of carbon from carbohydrate, shown by the reaction of sugar with sulfuric acid.

Supplemental Material Supplemental material for this article is available in this issue of JCE Online. It includes the full text (as originally published) of references 6, 8, 28, 33, 36, 39, 41, 42, 47, 48, and 53. W

Erica K. Jacobsen is an Assistant Editor of the Journal of Chemical Education.

Sucrose is dehydrated by sulfuric acid, producing a tall column of black carbon from the original carbohydrate.

A Cheetos snack chip is oxidized when it comes in contact with molten potassium chlorate.

Special online resources for high school teachers—just a CLIC away! Visit CLIC at http://JChemEd.chem.wisc.edu/HS/ We know you are pressed for time, so here is what you will find, quickly ! • Especially for High School Teachers • Classroom Activities • Tested Demos • Features • Laboratory Activities • JCE Software • JCE Internet JCE HS CLIC home page: http:// JChemEd.chem.wisc.edu/HS/

• JCE Index • and more!

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National Chemistry Week 2000: JCE Resources in Food Chemistry

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