El plaer de menjar cristalls: polimorfisme de la xocolata

Abstract

We are surrounded by crystals; minerals, jewels, everyday materials, technological devices such as mobile phones and computers, etc. There are also crystals in our bodies and crystals that we consume, such as salt and sugar, whose ordered structure is visible to the naked eye. Surprisingly, chocolate also contains crystals, and this research project deals with the study of the complex balance between the different crystalline forms (polymorphs) that this beloved substance adopts and the importance of controlling the conditions in its production to achieve the desired chocolate. The properties we appreciate in good chocolate such as texture and flavour, which make it one of greatest pleasures in life, depend on the structure of these crystals. In this project, we dive into the origin of chocolate and its evolution over time. We also cover the difficulty of obtaining the crystalline form, through artisanal and industrial processes, valued for its properties, and maintaining these properties over time without compromising its quality. It is known that chocolate seemingly deteriorates in the summer, through a phenomenon known as Fat Bloom, which is also studied in this project. In the experimental part, we induced the Fat Bloom, taking into account the type of chocolate, cocoa content, and whether it contains fillings or not. Interesting conclusions are drawn which contribute to keep this product in optimal conditions throughout the year.