Identification of fruity/fermented odorants in high-temperature-cured roasted peanuts

Gas chromatography/olfactometry on a concentrate of volatiles obtained by solvent-assisted flavor evaporation (SAFE) from roasted peanuts containing a fruity/fermented off-note was used to identify the odorants responsible for the flavor defect. Freshly dug peanuts were divided into two classes, mature and immature, using pod mesocarp color, and subjected to normal (27 degrees C) and high (40 degrees C) temperature curing. Sensory evaluation of the roasted peanuts found that immature peanuts cured at high temperature contained the fruity/fermented off-note. Mature peanuts cured at high temperature and both immature and mature peanuts cured at low temperature were free of the off-note. Peanuts with the off-flavor were found to contain fruit-like esters (ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, and ethyl 3-methylbutanoate) along with increased levels of short chain organic acids (butanoic, 3-methylbutanoic, and hexanoic). These findings were confirmed by sensory evaluation of models, where the addition of these compounds produced the fruity/fermented flavor defect in a control peanut paste. This is the first time that the odorants responsible for this off-note in roasted peanuts have been identified.