Comparison of &lt;sup&gt;19&lt;/sup&gt;F and &lt;sup&gt;1&lt;/sup&gt;H NMR spectroscopy with conventional methods for the detection of extra virgin olive oil adulteration

X Y Jiang,Q Q Chen,X C Weng,C Li

doi:10.3989/gya.1221172

Abstract

This paper reports the comparison of determination methods for extra virgin olive oil (EVOO) adulteration with two kinds of oils, refined olive oil (ROO) and soybean oil by 19FNMR, 1H NMR and chemical titration. The determination of adulteration of EVOO with ROO by 19F NMR was comparable to the conventional method. The contents of oleic, linoleic and linolenic acids of different oil samples can be determined by both 1H NMR and GC-MS. The results obtained from the two methods showed little differences. The adulteration of EVOO with soybean oil is detected by 1H NMR, although the limit of detection of the adulteration level is not less than 4.5%. The research demonstrates that 19F NMR can be a fast and convenient method to detect EVOO if it is adulterated with ROO and 1H NMR can be a fast and convenient method to detect EVOO if it is adulterated with seed oils.

Highlights

Olive oil is a vegetable oil produced in the Mediterranean Basin and is well-known for its nutritional value and health benefits (Pereira, 2013)
A total of 15 oil samples were purchased from local supermarkets, samples 1 to 6 were labeled as Extra virgin olive oil (EVOO) (3 samples imported from Spain, 3 samples imported from Italy)
The content in DGs of the various EVOO, refined olive oil (ROO) and seed oils (SO) were detected by 19F NMR

Summary

Introduction

Olive oil is a vegetable oil produced in the Mediterranean Basin and is well-known for its nutritional value and health benefits (Pereira, 2013). A number of previous studies suggested that olive oil exerts a protective effect against cardiovascular diseases, neurological disorders and certain malignant tumors (i.e. breast, prostate, endometrium, digestive tract) due to its well-balanced fatty acids, some trace nutritional components (squalene, phyto-sterols and so on) and natural antioxidants (Ruiz-Canela et al, 2011; Amel et al, 2016; Escrich et al, 2013). Extra virgin olive oil (EVOO) is considered to be the highest quality olive oil, in that it does not undergo any treatment other than washing, decantation, centrifugation and filtration. It has an acidity level which is expressed as oleic acid and does not exceed 0.8 % (Fragaki et al, 2005). The most common method for the determination of fatty acids in olive oils is gas chromatography, but it may be time-consuming and often require the initial methylation of samples (Aparicio et al, 2000)

Methods

Results

Conclusion