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

Introduction
The most common use of world peanut production remains the crushing of
peanuts for oil and meal. However, the proportion of peanuts used for other food
products has steadily increased (Revoredo and Fletcher 2002). The unique flavor of
roasted peanuts drives product marketing for products such as peanut butter and
confections. This flavor is the result of genetics, production, handling, storage, and
processing factors (Sanders and others 1995).
The main sources of volatile flavor compounds in peanuts are non-enzymatic
carbonyl-amine browning and lipid oxidation reactions, and include interactions
between peanut components as well as thermal decomposition products and loss of
volatiles (Hoffpauir 1953; Warner and others 1996). Maillard reactions are primarily
responsible for browning reactions in roasted peanuts, and produce pyrazines,
pyrroles, furans, and other low molecular weight compounds. In addition to Maillard
products, carbonyls are produced by Strecker degradation and oxidation, but can
then be lost by volatilization (Buckholz and others 1980). Pyrazines, which are
volatile heterocyclic nitrogen-containing compounds, are thought to be the major
flavor compounds impacting roasted peanut flavor (Warner and others 1996).
The causes of off-flavors in peanuts include lipid oxidation, induction of
anaerobic respiration, and external contamination with compounds such as
limonene, antioxidants, or insecticides (Ory and others 1992). Lipid oxidation is one
of the leading causes of off-flavors in raw and roasted peanuts, due to a high content
of unsaturated fatty acids (Warner and others 1996; Lee and others 2002).
Oxidation of the fatty acids in peanut oil can be caused by light, heat, air, metal
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