Changes in aroma characteristics during the preparation of red ginseng estimated by electronic nose, sensory evaluation and gas chromatography/mass spectrometry

Abstract

The changes in aroma characteristics during the preparation of red ginseng were investigated by using an electronic nose equipped with metal oxide (MO) sensor arrays, sensory evaluation and gas chromatography. All the MO sensor responses for fresh ginseng were much higher than those of steamed ginseng and most MO sensor responses for red ginseng were also higher than those for steamed ginseng when analysed using the electronic nose. It was evaluated by sensory panels that fresh ginseng had strong fresh, earthy, herbaceous and floral flavour notes while steamed ginseng had only moderate earthy flavour note and red ginseng had strong fragrant, sweet and roast flavour notes. A characteristic fragrant and sweet aroma compound was isolated from red ginseng and it was identified 3-hydroxy-2-methyl-pyran-4-one. The amount level of the aroma component in Korean red ginseng headspace was significantly correlated with either the SY/LG sensor response or the SY/AA sensor response of electronic nose at 1% level. These results suggest that the electronic nose equipped with MO sensor arrays may be also available for the rapid monitoring the changes in aroma characteristics during the preparation of red ginseng.