Effect of Ground and Roasted Parameters on Both the Microstructure of Arabica Coffee Beans and Coffee Infusion – An Imagistic Study

Abstract

Coffee is one of the most widely consumed beverages. Roasting is a baseline step in coffee processing, being involved in the development of color, flavor and taste for which coffee is appreciated. In addition, the roasting treatment triggers several complex physical changes inside the coffee bean, resulting in density decrease owing to volume increase, increase of beans brittleness, changes in coffee color, loss of bean mass and water, porosity increase, and governs coffee bean behavior during storage, grinding, and brewing. It is essential to examine physical changes, as coffee production is seasonal, and a long-term coffee storage is required. In the present study, the visual and microstructural differences between green and roasted Arabica coffee beans were investigated. The study of microstructural differences was performed using scanning electron microscopy, and clearly showed significant structural differences between green Arabica coffee beans and roasted Arabica coffee beans. The physical and structural modifications of infused coffee with water were explained through chromatic evaluation and microscopic analysis, respectively as function of ground size of roasted coffee beans and infusion time.