During the roasting of the fermented and dried beans several physical and chemical changes take place, which include the following:
*The bean losses moisture to about 2% final content
*The shell is loosened
*The nib (cotyledon) becomes more friable and generally darkens in color
*Sucrose hydrolysis which occurs during fermentation of the beans provides the reducing sugar pool important for aroma formation during roasting process.
*There is some degradation of the amino acids and proteins are partly denatured
*There is a loss of volatile acids and other substances that contribute to acidify and bitterness
*Additional reduction in the number of microorganisms present in the beans
The degree of change is related to the tine and temperature of roasting and to the rate of moisture loss during the process. Roasting conditions vary greatly according to the machine and product required.
Changes during roasting process
