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

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fact, Ory et al. (1992) suggested that the quality <strong>of</strong> volatiles in peanuts is easier to<br />

determine in raw peanuts, because volatiles formed during roasting may obscure<br />

smaller peaks.<br />

Roasted peanuts are susceptible to eventual fade in the flavor pr<strong>of</strong>ile, which<br />

may be due to lipid oxidation. Flavor-fade seems to be associated with the masking<br />

<strong>of</strong> pyrazines and other "roasted peanut" flavor compounds by large quantities <strong>of</strong> low-<br />

molecular weight aldehydes produced during lipid oxidation, such as hexanal,<br />

heptanal, octanal, and nonanal (Dimick, 1994). Eliminating or decreasing the rate <strong>of</strong><br />

flavor-fade requires understanding the relationships between carbonyl-amine and<br />

lipid oxidation reactions, as well as degradation and polymerization reactions <strong>of</strong><br />

heterocyclic nitrogen compounds (Warner et al., 1996).<br />

<strong>The</strong> proteins in peanuts may also be involved in <strong>of</strong>f-flavor formation. Basha<br />

et al. (1998) isolated a high molecular weight protein fraction from peanut seed<br />

which was involved in <strong>of</strong>f-flavor production during the roasting <strong>of</strong> peanuts. <strong>The</strong><br />

Maillard reactions <strong>of</strong> sulfur amino acids with carbohydrates can also cause sulfide or<br />

sulfur heterocyclic <strong>of</strong>f-flavors, although small amounts <strong>of</strong> these compounds can add<br />

positively to overall flavor (Sanders et al., 1995).<br />

Roasting Parameters <strong>Effect</strong> on Flavor<br />

Although current quality standards for roasted peanut flavor are based on<br />

seed color and changes in moisture content after roasting, other factors such as<br />

peanut genotype, harvest maturity, planting date, and improper curing and drying<br />

also affect roasted flavor (Baker et al., 2003). Pyrazine formation is increased by<br />

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