| The Chemistry
of Coffee The paper by Marino
Petracco provides a hearty blend
of molecules for this month. The author
deals with coffee at a number of different
levels ranging from the economic and
social to the still perplexing questions
of flavor and aroma. The associated
molecules demonstrate a range of structural
features that students will benefit
from examining in three dimensions.
Students encountering chemistry for
the first time are often dismayed and
confused by the range of shorthand representations
that we use to convey structural information.
Nicotinic acid, for example, is drawn,
in the paper and in essentially all other
print sources, as a regular hexagon.
Students should rightly ask how accurate
that representation is, and should be
encouraged to use the structure file
to measure the relative bond lengths
to see the deviation of the actual structure
from one with six equal-length sides.
The paper also serves as a rich source
of student projects in high school and
introductory college courses. Students
might be asked to pick one of the aroma
producing molecules, find other foods
containing that molecule, and look for
possible trends.
In addition to the static image, two
fully manipulable versions (Jmol, MDLChime)
of these molecules appear below. (The
Jmol versions may take a few extra seconds
to load, based on the speed of your Internet
connection.)
These and other molecules are avialable Only@JCE Online.
Download Chime (registration required)
|