Identification Of The Key Aroma Components And Authenticity Estimation Based On Flavor Fingerprint In Olive Oil

Olive oil is a kind of high-grade edible vegetable oils that is mainly produced in the Mediterranean area.It is popular for its rich efficacy and excellent taste.Due to the short history of olive cultivation in China,olive oil resource information is scarce.At the same time,the olive oil market is confusing due to the high cost of extra virgin olive oil leading to the adulteration action.Flavor is an important index to evaluate olive oil.This article aims to provide data support for its adulteration test from the perspective of flavor.Firstly,the quality indexes of olive oil such as acid value,peroxide value and UV absorbance are determined according to the national standard.According to GB23347-2009(olive oil,olive pomace oil),the selected 15 kinds of olive oil are all in compliance with the extra virgin standard.Secondly,this article has conducted in-depth exploration of volatile aroma compounds in olive oil.The aroma components in olive oil were extracted by solid phase microextraction(SPME)and solvent-assisted flavor evaporation(SAFE).Then,15 kinds of olive oil were detected by gas chromatography-olfactometry-mass spectrometry(GC-O-MS)with DB-WAX and DB-5 columns.A total of 90 flavor compounds were detected,and the key aroma components in olive oil were identified by aromatic extract dilution analysis(AEDA)and aroma activity value(OAV),which were hexanal,trans-2-hexenal,and UN1(grass),UN2(cooked potato),6-methyl-5-hepten-2-one,cis-3-hexenyl acetate,cis-3-hexen-1-ol,trans-2-heptenal and acetic acid and other small molecule compounds.Then seven of the key aroma compounds were determined quantificationally by external standards.Finally,electronic nose technology and flavor fingerprints of olive oil were applied to the adulteration estimation of olive oil.On the one hand,electronic nose combined with principal component analysis(PCA)and linear discriminant analysis(LDA)were used to differentiate and identify samples of olive oil and ones being adulterated with peanut oil,corn oil,and sunflower oil.The results showed that the electronic nose can be applied to the adulteration estimation of olive oil.For adulteration tests,it can distinguish the samples with more than 5% adulteration ratio.On the other hand,the characteristic datas obtained by SPME-GC-MS were used with traditional Chinese medicine chromatographic fingerprinting software to establish a standard fingerprint.The similarity of the sampleswas analyzed by the angle cosine and correlation coefficient methods to prove that the fingerprint was successfully constructed.Then,the above two similarity analysis methods and principal component analysis(PCA),partial least squares discriminant analysis(PLS-DA)were used to identify counterfeit samples.The optimal detectable adulteration rate was 20% of mixed oil sample.If a single brand of olive oil is used as a fingerprint,peanut oil samples with 10% adulteration rate can be detected by this method.Hence,electronic nose technology and flavor fingerprints had good effect on the the adulteration estimation of olive oil.