CHOCOLATE: A USEFUL MODEL FOR TEACHING BASIC TERMS ON CRYSTALLOGRAPHY AND THERMODYNAMICS

L. Bayés-García, M.A. Cuevas-Diarte, T. Calvet

University of Barcelona (SPAIN)
Although most people are aware of the satisfaction felt when eating a piece of chocolate, most people are not aware of the rich science that lies behind this desired food product.

Chocolate is mainly composed by cocoa mass (which basically consists of cocoa powder and cocoa butter), sugar and other additives (milk powder, vanilla, etc.). Among these components, cocoa butter becomes a key constituent of chocolate and responsible for many of its sensory attributes. Physical properties of chocolate, such as melting, rheology and texture, mainly depend on the crystal (polymorphic) forms present in cocoa butter. Thus, controlling the crystal forms present during the chocolate manufacturing and storage become necessary in order to obtain the desired characteristics of the end food product.

By using such a simple, attractive and sweet model, as chocolate is, many scientific concepts related to different disciplines, which are often understood as complex and dull by most students, may be introduced. In particular, the student may be able to develop crystallographic concepts and methodologies combined with some thermodynamic aspects, which have been historically known as complex and arduous disciplines. Hence, the student may enjoyably assimilate complicated concepts such as polymorphism, mixing behavior, crystal morphology, crystal size or thermodynamic stability, and may also be capable of understanding their application to daily life. These concepts may be applicable to any kind of material and can be more deeply developed depending on the level required.