Non-thermal plasma as preparative technique to evaluate olive oil adulteration

• NTP pretreatment of adulterated olive oil leads to a deviating headspace profile.
• NTP linked to HS-SPME-GC–MS results in detection of 28 marker volatiles of olive oil.
• Adulteration of olive oil with less than 1% sunflower can be classified.

In recent years adulteration of pure extra virgin olive oil (EVOO) with other types of vegetable oils has become an important issue. In this study, non-thermal plasma (NTP) is investigated as an innovative preparative analytical technique enabling classification of adulterated olive oil from an ascertained authentic batch of olive oil in a more sensitive manner. Non-thermal plasma discharges are a source of highly oxidative species such as singlet oxygen, and atomic oxygen. It was assumed that NTP-induced oxidation triggers unique lipid oxidation mechanisms depending on the specific composition of the oil matrix and minor constituents. In this work EVOO samples were adulterated with sunflower oil (1–3%) and submitted to NTP treatment. Results showed that while untreated samples could not be classified from the authentic olive oil reference, NTP treatments of 60 min (Ar/O2 0.1%) on the oil batches resulted in the formation of a unique set of secondary volatile lipid oxidation products enabling classification of adulterated oil samples.