New Orleans, Louisiana
June 26, 2016
June 26, 2016
August 28, 2016
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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