Browsing by Author "Kiros, Alemayehu"

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    Investigation on Effects of Roasting Temperature and Roasting Time on Caffeine Content in Coffee using Optical Method
    (Addis Ababa University, 2007-07) Kiros, Alemayehu; Asfaw, Araya (PhD)
    In this work a simultaneous determination of caffeine content was performed in sample of sidamo (Ethiopia) coffee, before and after roasting at either different temperature (140 􀀀 2100c) and different exposure time (4 􀀀 10 min) in order to investigate the effect on roasting temperature and roasting time on the content of caffeine content in coffee. A UV/VIS spectrophotometer method was used. A modest losses of caffeine was veri ed both in the roasting time and roasting temperature. Rate constant for chemical reactions at 2000c were determined. The result shows weight loss increases during roasting. For a pure caffeine molar decadic absorption coef cient and translational dipole moment were (1054m2=mol) and (12:78 0:71) cm respectively Key words: coffee, caffeine, roasting, uv/vis spectrophotometer, thermal