Article pubs.acs.org/jchemeduc
Cite This: J. Chem. Educ. XXXX, XXX, XXX−XXX
Chemistry of Candy: A Sweet Approach to Teaching Nonscience Majors Jennifer Logan Bayline,* Halie M. Tucci, David W. Miller, Kaitlin D. Roderick, and Patricia A. Brletic Department of Chemistry, Washington & Jefferson College, Washington, Pennsylvania 15301, United States
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S Supporting Information *
ABSTRACT: Candy, an everyday treat, is a convenient theme for teaching chemistry. Making candy incorporates solution concentration, colligative properties, and phase transformations while flavoring and color reflect synthesis or extraction. In this article, a nonscience major laboratory course on candy chemistry is presented. The course combines laboratory experiments and candymaking exercises, illustrating general chemistry principles and data collection. For example, students investigate crystal formation with rock candy and fudge, browning reactions with UV−vis spectroscopy and caramels, enzyme kinetics with polarimetry and cherry cordials, and freezing point depression with temperature measurements and ice cream. Imitation and natural flavors are obtained through Fischer esterification and distillation, respectively, while colorants are characterized through chromatography and spectroscopy. The course incorporates statistics through sensory analysis and color distribution. Student assessment and feedback as well as a poster/tasting session are also described. KEYWORDS: High School/Introductory Chemistry, Curriculum, Interdisciplinary/Multidisciplinary, Laboratory Instruction, Hands-On Learning/Manipulatives, Applications of Chemistry, Consumer Chemistry
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INTRODUCTION Candy is a confection based on sugar. Making it involves heating an unsaturated aqueous sugar solution to achieve a desired concentration through water evaporation followed by cooling. If heated to a high enough temperature and left undisturbed, glass formation can occur. If stirred, crystallization ensues. Additives can cause gelation, chemical reactions, or emulsification. Examples include gelatin (gelation), cream of tartar (sugar inversion), and milk proteins (emulsification). Colors and flavors are obtained through synthesis or extraction. As such, candy encompasses a variety of concepts and skills inherent to chemistry. Candy-based chemistry teaching appears in numerous guises. For example, candy has been used to teach stoichiometry,1,2 atomic orbitals,3 kinetics,4 and statistics.5 In this Journal alone, candy has been analyzed by calorimetry,6 liquid chromatography,7,8 and gas chromatography mass spectrometry.9 (Many other examples exist and are compiled in Supporting Information.) Weaving candy into the science classroom is often described10−12 and was even the theme for National Chemistry Week in 2014.13 Despite such an array of topics, an actual course on candy chemistry has not been reported in this Journal. While food chemistry is a common theme and often includes a candy unit,14,15 the only candy course we could find through an Internet search is a two-week technology one at the University of WisconsinMadison.16 In this article, we describe a laboratory candy chemistry course for nonscience majors. Offered during our three-week © XXXX American Chemical Society and Division of Chemical Education, Inc.
January term over the past four years, the course meets every week day for 3 h. The class comprises 12 students with one instructor and one student assistant and is held in both a foodsafe classroom (for candy exercises) and an organic chemistry laboratory (for nonedible experiments). It counts as a general laboratory requirement for graduation and is always fully enrolled with a wait list. Table 1 presents a list of topics, concepts, skills, exercises, and experiments included in the course. Candy recipes and explanations of the science behind them can be found in Supporting Information.
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CANDY SCIENCE The magic of candy making lies in sugar concentration and heating/cooling such that crystallization or an amorphous, sometimes glassy, state often results. The glass transition temperature (Tg) marks the temperature at which a hard amorphous substance, upon heating, becomes a soft, rubbery material. Sugar syrup can undergo such changes with the Tg of a candy dependent on the kind of sugar used, the molecular weight of the components, and the amount of water (plasticizer) present.17 LifeSavers have a relatively high Tg, resulting in a harder, crunchier candy.18 In contrast, caramels, with higher water content, have a lower Tg, leading to a more fluid, chewier candy. Moisture absorption impacts shelf life by lowering the Tg. If a candy is stored at a higher temperature Received: September 22, 2017 Revised: May 10, 2018
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DOI: 10.1021/acs.jchemed.7b00739 J. Chem. Educ. XXXX, XXX, XXX−XXX
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Table 1. Topics Covered in the Candy Chemistry Course Topic
Experiment/Candy Exercise
Candy Stages
Candy: Lollipops Candy: Sponge Candya Candy: Peanut Brittlea
Crystallization
Crystal Growth of Rock Candy Candy: Fudgea Sugar Effect on Caramelization and Maillard Reactions Candy: Caramelsa and Pralines Tracking Sucrose Inversion Through Optical Activity Candy: Cherry Cordials Hydrocolloids: Viscosity and Sweetness of Corn Syrups with Different Glucose Levels
Sugar Reactions
Special Additives and Techniques
Candy: Gumdropsa Candy: Taffya
Flavors
Preparation of Vanilla Extract Distillation of Essential Oil from Cloves Synthesis of an Artificial Flavor
Colors
Candy: Clove Hard Candya Chromatography of Artificial Dyes UV−Vis Spectroscopy of Artificial Dyes Candy Size and Color Distribution
Sensory Analysis
Other Confectionery Sweets
Candy: Hard Candya Color Taste Threshold of Different Sweeteners
Taste test: Effect of temperature on caramel Chemical reaction, hydrolysis; optical activity, polarized light, polarimeter; reaction kinetics, enzyme catalysis Hydrocolloids, hydrophilicity; molecular weight, chain branching, viscosity; Zahn cups Taste test: Effect of glucose level on corn syrup sweetness Taste test: Artificial vs natural orange flavors in gumdrops Aeration due to pulling Taste test: Effect of maximum temperature on taffy; effect of corn syrup viscosity/ sweetness on taffy Solvent extraction; unit conversion, percent weight Distillation; solvent extraction, phase separation, polarity; functional groups, infrared spectroscopy; yield Fischer esterification, chemical reaction, equilibrium, stoichiometry, yield; distillation; product extraction; functional groups, infrared spectroscopy Taste test: Artificial vs natural clove flavors in hard candy Paper chromatography; mobile vs stationary phases; chemical structure, polarity, retention factor Spectroscopy; light, wavelength, energy; absorbed vs transmitted color Gaussian distribution; descriptive statistics, confidence interval; volume estimate, number estimate, scatter plot Taste test: Effect of hard candy color on taste perception Sense of taste; supertaster, taste threshold; standard solution preparation; dilution, concentration Triangle test, paired comparison test, ranking test, statistics
Candy: Gumdrops,a Peanut Brittle,a Hard Candy,a Sponge Candya Candy: Fudge,a Caramel,a Taffya Quantitative descriptive analysis, spider/radar plot Candy: Chocolate Truffles Saturated vs unsaturated fatty acids; polymorphs Freezing Point Depression Candy: Ice Cream
a
Chemistry Concepts/Skills Amorphous solid; sucrose hydrolysis, acid catalyst Candy stages/phases; aeration due to chemical reaction Taste test: Effect of maximum temperature on sponge candy; artificial vs natural sweeteners in peanut brittle Solubility; supersaturation; crystallization, nucleation Taste test: Effect of agitation temperature on fudge Chemical reactions; UV−vis spectroscopy; temperature effect
Colligative properties, freezing point, solution concentration
Denotes candy that appears twice, as these exercises combine topics.
than its Tg, its viscosity decreases, causing deformation, volatile flavor molecule loss, and undesirable crystal growth or graining. In the food industry, first-order (e.g., boiling, solubilization) and second-order (glass) transitions are often compiled into a state diagram. Figure 1 provides a general representation of the phases/states that occur in sucrose−water mixtures, the basis for candy making.19 Here, a starting mixture (A) of sugar (sucrose), water, and other additives is heated to boiling (B). Water evaporates, leading to increased sugar concentration and boiling point elevation. Once a desired temperature/concentration is achieved (C), the mixture is cooled (D), resulting in supersaturation and reduced molecular mobility. If agitated (stirred), nucleation and crystallization occur (E1), perhaps resulting in a candy like fudge. (The concentration drops as sugar precipitates out of solution.) If undisturbed (or if doctoring agents that inhibit crystallization are present), reduced molecular mobility can immobilize the sugar mixture into a metastable glassy state (E2), leading to a product like hard candy.
Figure 1. State diagram of sucrose−water showing both first-order (boiling, solubilization) and second-order (glass) transitions that occur in candy making. Note that freezing/melting equilibria are not shown. Adapted with permission of Springer Nature and the author, R. W. Hartel (ref 19). Copyright 2001 Springer Nature.
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Table 2. Candy Stages and Temperatures at Which These Stages Occur
a Results of spooning the sugar syrup heated to a particular temperature range into cold water. bA solution of 3 cups of sugar and 1 cup of water were heated with red food coloring for better visualization. cThe light caramel stage appears pink because of red food coloring.
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CANDY STAGES
To investigate crystallization, students make rock candy, testing the impact of different conditions on crystal growth. They find that stirring results in smaller crystals, due to the creation of more nucleation sites (Figure 2). Temperature’s effect on crystals in fudge is also investigated. Students heat a fudge mixture, cooling it to one of three temperatures before stirring vigorously. They find the lowest temperature leads to grittier texture; the solution has been left too long, allowing larger, fewer crystals to grow. In contrast, higher agitation temperatures encourage the formation of numerous small
The competing forces between crystallization and glass formation can explain the general stages of candy making (Table 2).20 For example, heating a sugar syrup to 300 °F (149 °C) reaches the hard-crack stage, so named because the sugar syrup, if dropped into cold water, stretches into hard, brittle threads.21 Hard candy is made this way, with corn syrup included in the initial sugar syrup as a doctoring agent that inhibits crystallization. C
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Figure 2. Sugar crystals made from a supersaturated sucrose solution cooled to room temperature with (A) and without (B) stirring. Images obtained using a dissecting microscope with the inset showing individual crystals.
caramelization reaction is then demonstrated by making praline almonds.
crystals due to more nucleation sites, creating a smoother consistency (too hot, however, and the sucrose remains solubilized).
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SUGAR REACTIONS Sugar in food undergoes three primary reactions: Maillard, caramelization, and inversion. In the Maillard reaction, reducing sugars react with amino acids in proteins. The resulting brown color and products are responsible for the tasty brown flavor of roasted meat or crusty bread. Students investigate different sugars (monosaccharides and disaccharides) by combining them with the amino acid glycine and heating. Subsequent UV−vis analysis allows them to quantify which sugar yields the brownest (most desirable) color (Figure 3). They apply these concepts by then making Maillard-browned caramels. Figure 4. Effect of temperature on caramelization colors for fructose, sucrose (table sugar), and glucose when heated at 30 °F intervals. Fructose is seen to caramelize at a lower temperature with sucrose and glucose at higher ones. Note that caramelization occurs at much higher temperatures than the Maillard reaction.
Sucrose inversion is a hydrolysis reaction where sucrose breaks down into glucose and fructose (Scheme 1). The name Scheme 1. Sucrose Inversion in Which Sucrose (a Disaccharide) Hydrolyzes To Form Glucose and Fructose (Monosaccharides)
Figure 3. Bar graph showing the absorbance (430 nm) and colors of sugar solutions (1 wt %, aqueous) mixed with glycine and heated at 212 °F (100 °C) for 30 min. Monosaccharides (fructose, galactose, glucose) more readily undergo the Maillard reaction, as evidenced by their dark brown colors. Sucrose cannot, suggesting that the Maillard reaction in candy making is actually due to glucose and fructose, produced from sucrose inversion.
reflects the “inversion” of the optical rotation of polarized light from a positive value for sucrose to a negative one for an equimolar mixture of fructose/glucose. Typically catalyzed by acid or invertase, the reaction kinetics can be studied through NMR22 or a glucometer.23 Students use a polarimeter to record the optical activity of aqueous sucrose solutions over several days. They determine the rate at which conversion occurs depending on the amount of invertase (Figure 5). In a related exercise, students make cherry cordials, a candy whose liquid center is due to sucrose inversion. While significantly higher amounts of invertase are used (e.g., 1/4 teaspoon (tsp) is about 1,200 μL), the medium is different as the cordials contain very
Caramelization is another nonenzymatic browning reaction. Here, a sugar is heated until it undergoes pyrolysis reactions, again leading to new flavors and a brown color. To demonstrate the effect of temperature on this reaction, students heat either sucrose, fructose, or glucose, removing samples at various temperatures to document color change (Figure 4). The D
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Figure 6. Viscosity of three corn syrup brands, measured at 25 °C with Zahn cups. Sweetness was determined by summing the ranks (sweetest = 3; middle = 2; least = 1). The least viscous syrup was found to be the sweetest while the other two brands were indistinguishable in sweetness, highlighting the challenges with amateur taste testing. Figure 5. Specific rotation of 0.25 g/mL sucrose (aq) with 0−50 μL of invertase (above). The rate of sucrose inversion increases with greater amounts of invertase while no hydrolysis is seen for 0 μL. The same invertase is also tested in candy making. Cherry cordials (below) with 5/8 tsp of invertase have a liquid center after only 2 days whereas no such change is observed in cordials lacking invertase.
tincture in which a vanilla bean is soaked in ethanol (or vodka).26 Students also distill eugenol from cloves, determining percent yield based on material used. An alternative approach is synthesis. Fischer esterification in which an alcohol and a carboxylic acid are condensed to form an ester yields a variety of aromas. Students use this reaction to produce ethyl cinnamate (cinnamon), isobutyl propionate (rum), isopentyl acetate (banana), and methyl salicylate (wintergreen), though other options are also available.27,28 Showing students where flavors come from leads to discussion on natural versus imitation. While “natural” sounds better, a synthetic version can arguably be safer, consisting of one known chemical whereas extracted oils can contain hundreds in variable concentrations. To determine to what extent natural or imitation impacts taste, students make two versions of a particular candy, conducting a taste test to assess whether or not a difference can be detected. Gumdrops, for example, are made with either expressed orange oil or foodgrade limonene. Hard candy is used to test food-grade eugenol versus distilled clove oil while imitation and natural vanilla are assessed by making fudge or chocolate. In general, students were unable to distinguish between natural and imitation flavors. Additional concepts are functional groups and Fourier transform infrared spectroscopy (FTIR). Students obtain spectra of their distilled clove oil and synthesized ester and, through peak assignment, argue if the spectra support what their noses tell them.
little water while the polarimetry experiments are conducted with aqueous solutions.
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SPECIAL ADDITIVES AND TECHNIQUES Hydrocolloids are large hydrophilic macromolecules that swell or form gels when dissolved in water. In candy, these might be polysaccharides (starch, pectin, agar) or proteins (gelatin) and are responsible for the texture of jelly beans, licorice, gummies, and marshmallows. Students use gelatin to make gumdrops, observing how the candies swell as a result of hydrocolloids. Hydrocolloids also behave as thickeners, increasing the viscosity of a candy. For example, corn syrup is made from cornstarch, a polysaccharide, by partially breaking down the starch into small molecules of glucose (dextrose). The more glucose present in corn syrup, the lower the viscosity and the sweeter the taste.24 Students measure the viscosity of several brands of corn syrup using Zahn cups. They also conduct a ranking taste test,25 determining if runnier syrups are indeed sweeter (Figure 6). Given the presence of corn syrup in most candy recipes, correlating sweetness with viscosity is of importance in confectionery design. Aeration is a special technique in which a suspension of gas bubbles is trapped within the candy. Introducing these bubbles can involve chemical reactions. Students make sponge candy using sodium bicarbonate (baking soda) to generate carbon dioxide either through decomposition (heat) or reaction with an acid (vinegar). Another technique, pulling, is demonstrated by making taffy. Stretching the sticky sugar glass incorporates air, leading to the glossy, satin-like pastel color that results from light reflecting off these tiny bubbles.
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COLOR Candy color, in many ways, parallels flavor. Chemicals responsible for color can be obtained through both extraction and synthesis, inspiring a discussion on safety concerns. FD&C Red 2, for example, was banned in 1976 due to evidence that it causes cancer in laboratory animals while FD&C Yellow 5 and Yellow 6 are approved dyes that can cause allergic reactions.29 Color also relates to flavor by creating presumptions about how a food should taste. A red lollipop likely tastes of strawberry or cherry. Students test the relationship between color and flavor by creating hard candies with colors that deliberately do not match expected flavors. They assess their abilities to guess the correct flavor in a subsequent taste test.
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FLAVOR Flavors can be obtained through extraction or synthesis. Two extraction techniques include solvent extraction and distillation. To illustrate the former, students make vanilla extract, a E
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Figure 7. Paper chromatography of FD&C Red 40, Yellow 5, Blue 1, and McCormick Black food coloring with matching UV−vis spectra. Both techniques demonstrate that McCormick black is a mixture of the red, yellow, and blue FD&C dyes. The paper chromatography is an artistic rendition of an actual experiment.
Figure 8. Spider plots showing the differences between five attributes of (A) caramels and (B) taffy. For caramels, heating temperatures were tested and found to impact taste. For taffy, different corn syrup brands ultimately led to minimal variations in taste.
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Two common experiments concerning food dyes appear in this Journal: chromatography30−32 and spectroscopy.33−36 Our students conduct a paper chromatography experiment, determining the components present in each dye. They correlate these results with UV−vis spectroscopy, investigating how absorbed wavelengths relate to colors (Figure 7). The color of candy is convenient for teaching statistics. Students count the number of M&M’s of each color in bags and use statistics to assess color distribution.37 They also measure the volume of 10 M&M’s in a graduated cylinder, repeating this several times, to generate a plot of number vs volume. From this, the number of M&M’s in a jar is estimated. Students thus learn about Gaussian distribution, average, standard deviation, t testing, and the meaning of significant differences as well as basic graphing skills.
SENSORY ANALYSIS
The sense of taste stems from taste buds found in papillae (bumps) on the tongue. It is believed that supertasters, showing extreme sensitivity to flavor, have a higher density of papillae.38 Students measure the density of papillae on their tongues to identify if they are supertasters.39 They also conduct a threshold test to determine the lowest concentration at which they detect flavor using serial dilutions of sugar and artificial sweeteners (aspartame, erythritol, fructose, saccharin, sucralose).40 The structural difference between sucralose and sucrose and the impact on sweetness are further emphasized by using these sweeteners to make peanut brittle and judging the resulting flavor. Describing a candy’s taste requires sensory analysis, used in the food industry to assess quality control, product development, and correlation with measured parameters (physical or F
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chemical).25 Analytical tests involve trained testers who determine if there are differences between samples and the nature and magnitude of these differences. Consumer tests comprise a representative sample from a target audience and focus on acceptance, preference, or degree of liking for a product. Students employ several of these methodologies throughout the course. For example, a triangle (difference) test in which the odd sample in a group of three (where two samples are the same) is identified is used to assess natural vs synthetic flavors in gumdrops, hard candy, chocolate, and fudge.41 Quantitative descriptive analysis (QDA) is also done to generate a flavor profile. Students rate five characteristics on a scale of 1 (least) to 5 (most), producing a spider (or radar) plot.41 Taste test results for caramels (Figure 8A) demonstrate an impact of cooking temperature while different corn syrup brands are shown to not affect taffy (Figure 8B).
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Figure 9. Students present posters on candy science, displaying their confections for tasting at the end of the course. Photographs used with permission from S. Dudik. Copyright 2017.
OTHER CONFECTIONERY SWEETS No candy course would be complete without chocolate, a topic that easily merits its own course. Chocolate consists of cocoa butter, a fat known to crystallize into six different polymorphs.42,43 These crystalline forms vary in density and energy, leading to differences in taste, texture, and appearance. Tempering is the careful process of heating and cooling that yields the most desirable form, resulting in shiny, smooth chocolate that breaks with a snap and melts in the mouth. Our students make their own chocolate from more basic components of cocoa powder, cocoa butter, and sugar. Their level of success in tempering is based on appearance and whether or not bloom (marking a transition to a less desirable polymorph) is seen. Ice cream is another popular confection that relies on freezing point depression. Students measure the freezing point of different amounts of salt and ice, determining the optimal ratio needed for the coldest temperature. Using this information, they make ice cream using rock salt. A fun variation of this activity involves making ice cream with liquid nitrogen, as described in Supporting Information.
change in attitudes. For example, both before and after the course, students expressed interest in candy chemistry (n = 12, tstat 0.24, p 0.81), perceived the level of difficulty to range from normal to hard (tstat 1.66, p 0.11), and judged the amount of work to be a little more than other courses (tstat 0.66, p 0.51). Most of them (75%) stated that fulfilling the graduation requirement was their primary reason for taking the course though half of them remarked they would consider taking another science course if designed for nonscience majors. Students enjoyed making taffy and fudge the most because they were fun and tasty. The clove hard candy was least popular because of its flavor. The favorite laboratory experiment was color chromatography, so voted for being “an interesting topic”. The least popular was the ester synthesis as the students found the concepts difficult to understand. Some of the comments on course evaluations were “I enjoyed [the course] more than I would any random chemistry class. Learning these concepts through candy making was fun, especially for someone who doesn’t like science.” Another was “I really enjoyed making the candyit allowed me to put the concepts to use.” Especially rewarding was the “I am more interested in chemistry now.”
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STUDENT ASSESSMENT For this laboratory-only course, students are graded on reports (50%) consisting of the laboratory notebook and postlab analysis. Candy-making exercises are not graded, but students are held accountable for the concepts and skills as these are included on a final exam (15%). Safety and technique represent 10%. The course ends with students presenting posters (15%) on candy-related chemistry topics. Past examples include browning reactions, natural vs synthetic flavors, sensory analysis, and hydrocolloid viscosity. During this session, they present their candy in a decorated candy box (10%), asking the general audience to rate the quality of their sweets (Figure 9), an assessment that becomes part of their grade. Liquid nitrogen ice cream is also served.
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CONCLUSION A nonscience major laboratory course on candy chemistry is presented. This topic covers an array of concepts, including crystallization and glass transition, colligative properties, supersaturated solutions, color and flavor analysis, chemical reactions, extraction techniques, and statistics. Numerous extensions of the course are detailed in Supporting Information, with possibilities ranging from the high-school level up to an advanced instrumental analysis laboratory. The course has been well-received and is a popular option for students seeking a general science graduation requirement. In addition, the poster and candy tasting session at the end provides the opportunity to share this sweeter side of chemistry with a wider audience.
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EVALUATION OF COURSE In the past two offerings of the course, 79% of the students were seniors, and 42% were either business, economics, or accounting majors (unsurprising given that ∼35% of our students graduate with these majors). Pre- and postcourse surveys were administered to students in the 2017 offering. Independent sample t tests (α = 0.05) showed no significant
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available on the ACS Publications website at DOI: 10.1021/acs.jchemed.7b00739. G
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(17) Hartel, R. W. Crystallization in Foods; Aspen Publishers: Gaithersburg, MD, 2001; pp 138−141. (18) Hartel, R. Sweet Science: Having Fun with Candy Chemistry. ACS Webinars [Online]; American Chemical Society, October 15, 2014. https://www.acs.org/content/acs/en/acs-webinars/culinarychemistry/candy-chemistry.html (accessed May 2018). (19) Hartel, R. W. Controlling Crystallization. Crystallization in Foods; Aspen Publishers: Gaithersburg, MD, 2001; pp 251−252, 270− 271. (20) Corriher, S. O. Cookwise: The Hows and Whys of Successful Cooking, 1st ed.; William Morrow and Company, Inc.: New York, 1997; pp 421−476. (21) Dropping hot sugar syrup into cold water is known as the “water test” and was used by confectioners prior to the existence of reliable candy thermometers. The highest temperature the sugar syrup attains indicates a certain concentration, dictating the type of candy that will form. (22) Kehlbeck, J. D.; Slack, C. C.; Turnbull, M. T.; Kohler, S. J. Exploring the Hydrolysis of Sucrose by Invertase Using Nuclear Magnetic Resonance Spectroscopy: A Flexible Package of Kinetic Experiments. J. Chem. Educ. 2014, 91 (5), 734−738. (23) Heinzerling, P.; Schrader, F.; Schanze, S. Measurement of Enzyme Kinetics by Use of a Blood Glucometer: Hydrolysis of Sucrose and Lactose. J. Chem. Educ. 2012, 89 (12), 1582−1586. (24) Hobbs, L. Sweeteners from Starch: Production, Properties and Uses. In Starch: Chemistry and Technology, 3rd ed.; BeMiller, J., Whistler, R., Eds.; Food Science and Technology; Elsevier: New York, NY, 2009; pp 797−832. (25) Guinard, J. X.; Robertson, I. Sensory Evaluation for Brewers. In Evaluating Beer; Brewers Publications: Boulder, CO, 1993; pp 55−74. (26) Kitchen Projects. Vanilla Extract Recipe. http://www. kitchenproject.com/vanilla/4FoldVanillaExtract.htm (accessed May 2018). (27) Epstein, J. L.; Castaldi, M.; Patel, G.; Telidecki, P.; Karakkatt, K. Using Flavor Chemistry To Design and Synthesize Artificial Scents and Flavors. J. Chem. Educ. 2015, 92 (5), 954−957. (28) Bromfield-Lee, D. C.; Oliver-Hoyo, M. T. An Esterification Kinetics Experiment That Relies on the Sense of Smell. J. Chem. Educ. 2009, 86 (1), 82−84. (29) Sharma, V.; McKone, H. T.; Markow, P. G. A Global Perspective on the History, Use, and Identification of Synthetic Food Dyes. J. Chem. Educ. 2011, 88 (1), 24−28. (30) Kandel, M. Chromatography of M & M Candies. J. Chem. Educ. 1992, 69 (12), 988−989. (31) Emry, R.; Curtright, R. D.; Wright, J.; Markwell, J. Candies to Dye for: Cooperative, Open-Ended Student Activities to Promote Understanding of Electrophoretic Fractionation. J. Chem. Educ. 2000, 77 (10), 1323−1324. (32) Birdwhistell, K. R.; Spence, T. G. A New Glow on the Chromatography of M&M candies. J. Chem. Educ. 2002, 79 (7), 847. (33) Aurian-Blajeni, B.; Sam, J.; Sisak, M. Sweet Chemistry. J. Chem. Educ. 1999, 76 (1), 91−92. (34) Sigmann, S. B.; Wheeler, D. E. The Quantitative Determination of Food Dyes in Powdered Drink Mixes. J. Chem. Educ. 2004, 81 (10), 1475−1478. (35) Stevens, K. E. Using Visible Absorption To Analyze Solutions of Kool-Aid and Candy. J. Chem. Educ. 2006, 83 (10), 1544−1545. (36) Erhardt, W. Instrumental Analysis in the High School Classroom: UV-Vis Spectroscopy. J. Chem. Educ. 2007, 84 (6), 1024−1026. (37) Ryan, S.; Wink, D. J. JCE Classroom Activity #112: Guessing the Number of Candies in the JarWho Needs Guessing? J. Chem. Educ. 2012, 89 (9), 1171−1173. (38) Bartoshuk, L. M.; Duffy, V. B.; Miller, I. J. PTC/PROP Tasting: Anatomy, Psychophysics, and Sex Effects. Physiol. Behav. 1994, 56 (6), 1165−1171. (39) Science Buddies. Super-Tasting Science: Find Out If You’re a “Supertaster”! Scientific American; Dec 27, 2012. https://www.
Candy-making tips, candy recipes with scientific explanations, additional candy resources and experiments, and course syllabus (PDF, DOCX)
AUTHOR INFORMATION
Corresponding Author
*E-mail: jbayline@washjeff.edu. ORCID
Jennifer Logan Bayline: 0000-0002-0045-1261 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The authors would like to thank the candy chemistry students for their participation and tasty confections over the last four years. The authors also thank Prof. R. Hartel (University of WisconsinMadison) for his suggestions and advice.
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DOI: 10.1021/acs.jchemed.7b00739 J. Chem. Educ. XXXX, XXX, XXX−XXX
