Abstract SCHIRACK, ANDRIANA VAIS. The Effect of Microwave ...

(Pawliszyn, 2000). Also, the elevated temperatures used during distillation can
cause the formation of artifacts, such as Maillard or Strecker compounds when
sugars and free amino acids are present. While distillation utilizes differences in
vapor pressure, solvent extractions and chromatography utilize differences of
distribution equilibria (Teranishi, 1998). After Dupuy et al. (1971) developed a direct
GC method to analyze peanut flavor, a database was then developed to establish a
"normal" peanut volatiles profile of good quality raw peanuts which have few
breakdown products of lipid peroxidation. Since the 1950’s, the number of
compounds characterized for their flavor properties has grown from 500 to 15,000,
due to the advent of gas and liquid chromatography, infrared, nuclear magnetic
resonance, and mass spectrometry (Teranishi, 1998).
Direct sample introduction methods in GC have generally employed
headspace sampling, in which gas samples at ambient or elevated temperatures are
drawn off from the headspace of a sample in a gas-tight syringe and injected directly
into the GC (Waltking and Goetz, 1983). Headspace techniques target very volatile
and abundant compounds, which can otherwise be lost during extraction, and these
techniques can be conducted at very low temperatures to prevent artifact formation
(Reineccius, 2002). Headspace techniques can also be beneficial due to speed of
operation; for example, Young and Hovis (1990) developed a rapid headspace
method to determine objectionable flavor defects in peanut samples at the rate of
four per hour.
Sample sensitivity in headspace analysis has been enhanced using dynamic
headspace or purging techniques (Waltking and Goetz, 1983). Purge and trap
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