Variation in colour of arabica coffee during roasting at different heating conditions

In this study, variation in colour was evaluated for both whole and ground coffee beans. Results showed that the behaviour of colour parameters changes when pyrolysis begins. Luminosity decreases during roasting and decreases more rapidly during thepyrolysis stage. Ground coffee presented higher luminosity values compared to whole roasted beans which showed that darkening occurs from the outside towards the inside of the bean. It was also observed that bean colour tends to become more uniform towards the end of the roasting process. Results indicate that the reactions that cause the changes in colour of the coffee beans are controlled by the heating conditions employed during roasting. Prolonged heating resulted in a more distinguished decrease in colour parameters.