Abstract:
Coffee is one of the most widely consumed beverages around the world. Coffea arabica
and Coffea robusta are the two common coffee varieties that have grown in commercial
production and both of them are differed distinctly in flavor, caffeine contents and other
phytochemical compounds such as chlorogenic acid and antioxidants, which are having
beneficial properties and allowed coffee to be a functional food. This study aimed to
determine the effect of temperature and time profile of roasting on the quality of instant
coffee cubes prepared from Coffea robustas and to determine the appropriate treatment
(roasting time-temperature combination) out of the three treatments to obtain the
best instant coffee cube. Several important phytochemical parameters, shelf life and
sensory attributes were evaluated after the production of instant coffee cubes using
Association of Official Analytical Collaboration (AOAC) standard methods, Sri Lanka
Standards (SLS) 516 and using 30 untrained panelists with a 9-point hedonic scale
respectively. Output from the three treatments; Treatment 1: roasting temperature
of 80°C for 45 minutes, Treatment 2: roasting temperature of 140°C for 30 minutes
and Treatment 3: roasting temperature of 220°C for 10 minutes showed significant
impact on some parameters. The treatment of roasted temperature at 220°C for 10
minutes was the best treatment to produce instant coffee cube with higher coffee liquor
concentration converted from higher fat content of 12.15%, with least water activity
of 0.7574, comparatively higher caffeine content of 2.21%, carbohydrates content of
63.46%, water activity 0.7574, pH of 5.58; Total Soluble Solids 34. However instant coffee
cubes produced from the third treatment (at 220°C for 10 minutes) had low antioxidant
activity and low Chlorogenic acid content of 0.88±0.4 compared to the other treatments
although sensory panelists prefer instant coffee cubes made from the third treatment
which have better shelf life attributes.
