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

strong roasted flavor in peanuts (Leunissen et al., 1996; Buckholtz et al., 1980).
Methylpropanal, methylbutanal, dimethylpyrazine, and methylethylpyrazine have
been related to dark roasted flavor in peanuts (R> 0.84) using both a dynamic
headspace technique and direct GC (Crippen et al., 1992). Pyrazine
measurements, rather than Hunter LAB value, have also been used with increased
accuracy in relating peanut aroma and flavor in industrial processing, where a mix of
genotypes may be used (Baker et al., 2003).
Several efforts have been made to tie specific pyrazines to the sensory
“roasted peanutty” characteristic. Mason and Johnson (1966) suggested that
trimethylpyrazine or 2-methyl-5-ethylpyrazine might be responsible for the
characteristic roasted note in peanuts. 2, 3, 5-trimethylpyrazine appears also to be a
good indicator of roasted peanut flavor especially in Florida MDR 98 peanuts (Baker
et al., 2003). However, in peanuts roasted above 150 °C, 2,5-dimethylpyrazine had
a high correlation with roasted peanut flavor and aroma, as compared to L-values,
for all genotypes of peanuts tested (Baker et al., 2003). Methylpyrazine is
associated with the sensory characteristic of "roasted" and is desirable at low
concentrations; however, at higher concentrations of methylpyrazines as well as
other pyrazines, the flavor becomes more bitter (Leunissen et al., 1996).
The peanuts used for roasting are a mix of genotypes, seed sizes, maturities,
and seed composition, so establishing the relationship between volatile compounds
and roasted peanut flavor would allow for roasting optimization (Baker et al., 2003).
However, not only are pyrazines the most substantial compound tied to positive
characteristics in roasted peanuts, they also function to obscure some off-flavors. In
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