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

et al., 1980). Likewise, sugars present can undergo caramelization or can be
degraded (Hoffpauir, 1953).
The volatiles produced by roasting have been classified into three groups
(Ory et al., 1992): those which increase in production rate over a wide range of
temperatures (such as methanol, acetaldehyde, 3-methylbutanal, N-methylpyrrole,
and 3- carbon substituted pyrazines), those produced at low concentrations at
temperatures below 142 °C (2-methylpropanal, dimethylpyrazine, 4-carbon
substituted pyrazines, benzene acetaldehyde), and a third group which is little
affected by an increase in roasting temperature (ethanol and lipid oxidation
products).
Pyrazines, which are volatile heterocyclic nitrogen-containing compounds, are
the major flavor compounds impacting roasted peanut flavor (Warner et al., 1996;
Baker et al., 2003). Pyrazines and a pyrrole were first identified in roasted peanuts
by Mason and Johnson (1966) by making aqueous condensates of stripped volatiles
of Spanish peanuts, and subsequent analysis by gas chromatography-mass
spectrometry (GC-MS). Nuclear magnetic resonance, ultraviolet detection and mass
spectrometry were used to identify methylpyrazine, 2, 5-dimethylpyrazine,
trimethylpyrazine, ethylmethylpyrazine, dimethylethylpyrazine, and N-methylpyrrole
in roasted Spanish peanuts (Mason and Johnson, 1966). Through vacuum
degassing of pressed, roasted peanuts followed by GC-MS, IR and UV identification,
Johnson et al. (1971) first identified 19 alkylpyrazines present in the basic fraction of
roasted peanuts. Most of the alkyl pyrazines reported were attributed to browning
reactions. However, the formation of 2-phenyl-2-alkenal was attributed to aldol
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