Why McDonald's fries taste so good Apr 25 2011 Today's
sophisticated spectrometers, gas chromatographs, and headspace-
vapor analyzers provide a detailed map of a food's flavor
components, detecting chemical aromas present in amounts as low
as one part per billion. The human nose, however, is even more
sensitive. A nose can detect aromas present in quantities of a
few parts per trillion -- an amount equivalent to about
0.000000000003 percent. Complex aromas, such as those of coffee
and roasted meat, are composed of volatile gases from nearly a
thousand different chemicals. The smell of a strawberry arises
from the interaction of about 350 chemicals that are present in
minute amounts. The quality that people seek most of all in a
food -- flavor -- is usually present in a quantity too
infinitesimal to be measured in traditional culinary terms such
as ounces or teaspoons. The chemical that provides the dominant
flavor of bell pepper can be tasted in amounts as low as 0.02
parts per billion; one drop is sufficient