New Orleans, Louisiana
June 26, 2016
June 26, 2016
June 29, 2016
978-0-692-68565-5
2153-5965
Materials
14
10.18260/p.25482
https://peer.asee.org/25482
2283
Cynthia Barnicki is a professor in Mechanical Engineering at the Milwaukee School of Engineering and currently the interim chair of the Mechanical Engineering Department. She holds a Ph.D. degree in Metallurgical Engineering from the Ohio State University. Cindy teaches courses in materials, manufacturing processes, and engineering design and is currently the program director for the Bachelor of Science in Engineering program. In addition to her teaching experience, she has industrial experience in quality management and production problem solving at Martin Marietta Energy Systems, and later GE Superabrasives. Cindy is active in assessment and accreditation activities at MSOE and has been exploring ways to include on-line education in her classes.
Katherine Wikoff is a professor in the General Studies Department at Milwaukee School of Engineering, where she teaches courses in communication, literature, film studies, and political science. She has a B.A in Political Science from Wright State University and an M.A. and Ph.D. in English from the University of Wisconsin-Milwaukee.
Dr. Anne-Marie Nickel is a Professor of Chemistry at the Milwaukee School of Engineering (MSOE). In 2002, she earned her Ph.D. in Inorganic Chemistry from the University of Wisconsin-Madison. She earned her B.A. in Chemistry at Lawrence University in Appleton, Wisconsin in 1997. Dr. Nickel is a member of the ASEE and the American Chemical Society (ACS).
e-mail:nickel@msoe.edu
Chocolate is a material that is typically not associated within an engineering curriculum. Yet when viewed as a material that has composition, structure, and properties, the topic can add interest and an alternative perspective to a traditional materials engineering or chemistry course. Additionally, chocolate as a technical topic in a humanities course can serve as a starting point for exploration of associated aesthetic, social, and cultural concepts. The structure of the cocoa butter in chocolate, which is polymorphic, is critical in achieving good chocolate—and only the β’ phase is desired. The recipes (processing) for chocolate can be related to nucleation and growth theory in a similar manner to solidification and heat treatment of metals; and also can be related to molecular issues in a chemistry class including solutions, colligative properties, polymeric materials and chemical reactions. The main ingredient in chocolate originates as an agricultural product from tropical regions where trade, labor and sustainability practices are widely variable.
The paper will provide an overview of chocolate as a material including a description of the main ingredients, the types of chocolate, the processing of the cocoa nut to chocolate ingredients, the structure of chocolate as a candy and a description of the different phases of cocoa butter and the influence of the cocoa butter phase on the properties of the finished chocolate product. The unique nature of the molecular structure of the cocoa butter and the resulting properties will be covered from the perspective of both chemistry and materials engineering. The paper will describe what happens when chocolate is allowed to soften and cool in an uncontrolled fashion, which is called fat blooming, and also what is known as the “tempering” process, which is the thermal process used to achieve the desired β’ phase and relate both of these process to nucleation and growth theory.
Additionally, the paper will discuss sourcing issues with sustainability due to ethical concerns (for example, the child labor associated with cocoa farming), controversy in trading practices (despite international regulation), and the cultural and political environments of the countries where cacao trees are grown.
The paper will conclude with some ideas and examples of using this topic for outreach to different audiences to increase the interest in STEM fields.
Barnicki, C. W., & Wikoff, K. H., & Nickel, A. (2016, June), How Study of Chocolate as a Material Can Be Used to Enhance Engineering Education Paper presented at 2016 ASEE Annual Conference & Exposition, New Orleans, Louisiana. 10.18260/p.25482
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