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

e high enough for pyrazine formation, and could explain the increased formation of
phenylacetaldehyde and guaiacol.
Interestingly, lipid oxidation compounds did not appear to have a role in
microwave-related off-flavor. This is consistent with the literature, as Katz (2002)
found that microwave-blanched peanuts were more oxidation stable than oven-
blanched peanuts as evident by lower peroxide values and higher oxidative stability
index. In addition, Maillard reaction products in peanuts such as reductones are free
radical scavengers which could further prevent formation of oxidation products
(Sanders and others 1993).
Model systems
In order to examine the effects of these compounds at their relative
concentrations in a food matrix, phenylacetaldehyde, guaiacol, and 2,6-
dimethylpyrazine were added singly and in combination to a freshly roasted peanut
paste free of off-flavors (Table 2). Although these compounds individually had
distinct aromas during GC/O of rosy (phenylacetaldehyde), smoky/burnt (guaiacol),
and nutty/earthy (2,6-dimethylpyrazine), the flavor profile of the reference paste
changed in different ways upon compound addition, emphasizing the effect of
compound concentration and the effect of other components in the matrix.
In aroma evaluation, 6 out of 6 panelists agreed that the addition of
phenylacetaldehyde, guaiacol, and 2,6-dimethylpyrazine singly at the average
concentrations found during quantification, created notable and negative differences
from the control. In each of these models, a decrease in roasted peanutty aroma
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