March Speaker (See the March 2010 Newsletter for more detail)
When: Monday, March 15, 2010
“Chemistry of Coffee ”
Venue: 548 Hamilton Hall, University of Nebraska-Lincoln Campus
Time: 6:30 pm
The seminar will present a brief history of coffee, the physical process from cherry to brewed coffee and espressos. The final product of the harvest is the green "bean", which has a characteristic odor (green coffee beans will be passed around during the presentation). The roasting of the beans is dominated by the Maillard reaction and Strecker degradation. Some of the compounds that have been identified as important flavor and aroma compounds are β-damascenone (cooked apple), 2-furfurylthiol (the dominant "coffee" smell of freshly brewed coffee), 2-isobutyl-3-methoxypyrazine (earthy), guaiacol (spicy), 2,3-butanedione (artificial butter), and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel). The stage at which roasting is stopped has traditionally been done by color (after roasting test batches). The whole roasting process takes place 8-12 minutes, followed by rapid cooling to slow further reactions. Coffee roasted by the speaker (in his office!) will be sampled. All coffee drinkers know that leaving coffee on a burner rapidly ruins the brew. This chemistry will be discussed, as will "staling" - the degradation of roasted coffee by exposure to air.The final part of the talk will be a discussion of the health issues surrounding coffee. The compounds cafestol and kahweol can raise cholesterol slightly, but are absorbed by paper filters.
Biographical Sketch: Tracy P. Hamilton is the Associate Professor in Department of Chemistry at University of Alabama. He received his B.S. Degree from the University of Arkansas at Little Rock in 1980. After two years of graduate study and one year in a consulting laboratory, he worked with Peter Pulay in quantum chemistry at the University of Arkansas in Fayetteville, obtaining his Ph.D. in 1987. He then enjoyed a four-year stint doing further research in quantum chemistry with Henry F. Schaefer III at the University of Georgia. Dr. Hamilton joined the Department of Chemistry at UAB in 1991. Dr. Hamilton is also a member of the Center for Free Radical Biology. Dr. Hamilton’s research involves the development of theoretical methods to study chemical systems by quantum mechanics, with an emphasis on techniques for studying larger molecules. His research also includes the application of these methods to chemical systems. Dr. Hamilton did not drink coffee until after he obtained a faculty position at UAB. He expanded his personal interest in home made beverages to include coffee roasting in 2006.
For questions, please contact the host: James Takacs, jtakacs1@unl.edu (402) 472-3634
