Abstract
A new method for determination of unchanged chlorogenic acids in roast coffee was established based on the specific green coloration of caffeic acid esters in ammonia alkalinity. A. Two ml of 1M NH4Cl-NH4OH buffer solution (pH 9.1) was added to 10ml of the extract. After shaking for 7 hours at 30°, the optical density at 620nm was measured. B. The optical density at 620nm on the mixture of 2ml of 0.5M Na2HPO4-Na2CO3 buffer solution (pH 9.1) and 10ml of the extract was measured by the same procedure. The difference of absorption between A and B was in linear with concentration of chlorogenic acid to 70mg/100ml. But the absorption with isochlorogenic acid was twice as much as chlorogenic acid, resulting that the content of chlorogenic acids in roast coffee was equal to 0.72 times the content calculated as chlorogenic acid. Percentages of unchanged chlorogenic acids in the various roast coffee determined by this method were as follows; Medium roast, av. 3.66, French roast, 2.75, Italian roast, 0.16.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
