Rancidity evaluation and shelf-life monitoring of virgin olive oil by electronic-nose

This study was carried out to evaluate the applicability of Electronic Nose (EN) for the rapid and objective evaluation of rancidity in virgin olive oils and to monitor the shelf-life of bottled virgin olive oils. An EN equipped with an array of 10 electronic chemical sensors with partial specificity and an appropriate pattern-recognition system was tested. The results obtained by the EN were compared with those obtained by the sensory assessment and those obtained by the GC/MS analysis of volatile markers of oxidation. Analytical parameters of EN were optimized: volume of the flask and sample amount, time and temperature of analysis, data collection interval. Principal component analysis (PCA) was applied to a first data sets evaluation. Usefulness and limits in applying the EN for the screening among different quality oils (extra virgin, virgin and lampante) and to evaluate the rancidity development defect in bottled virgin olive oil during 12 month storage are discussed.