DEVELOPMENTS IN ANALYTICAL METHODS AND MANAGEMENT Is it possible to use an ‘‘electronic nose’’ for the detection of sensorial defects in virgin olive oil?

Abstract

The aim of our study was to see if electronic nose (EN) can help sensory analysis panel for a first screening of virgin olive oils in order to detect samples with sensory defects. Nearly 80 samples were evaluated by sensory analysis ITERG’s panel according to CEE 2568/91 method, and analyzed with FOX 3000 Alpha MOS electronic nose. These samples were also analyzed by GC and GC/MS in order to identify and quantify components of the headspace. With the EN used, it was impossible to get discrimination between samples of the four different grades : “extra virgin”, “virgin”, “ordinary” and “lampante”. Moreover, when diluting “lampante” samples in two different “extra” virgin olive oils, sensors were more sensitive to the differences between the two “extra” oils than those between sensory defects. To understand EN results, partition coefficients in olive oil/air at 50°C were evaluated. Static headspace is rich in alcohols (methanol, ethanol), poor in aroma components such as t-2-hexenal, hexanal, 3-methyl-butanol or 1-octen-3-ol. These results explain why chromatograms of “extra” and “lampante” oils are scarcely different. In conclusion, EN coupled with static headspace is not able to detect sensory defects of virgin olive oil at the moment.

Keywords

• virgin olive oil
• electronic nose
• sensory analysis
• static headspace
• gas chromatography