Authentication of the Botanical and Geographical Origin and Detection of Adulteration of Olive Oil Using Gas Chromatography, Infrared and Raman Spectroscopy Techniques: A Review.

Eleni Kakouri,Christos S Pappas,Dimitra Daferera,Charalabos Kanakis,Petros A Tarantilis,Panagiota-Kyriaki Revelou

doi:10.3390/foods10071565

Eleni Kakouri, Christos S Pappas + Show 4 more

Open Access

https://doi.org/10.3390/foods10071565

Copy DOI

Journal: Foods (Basel, Switzerland)	Publication Date: Jul 6, 2021
Citations: 11	License type: CC BY 4.0

Affiliation: Agricultural University of Athens

Abstract

Olive oil is among the most popular supplements of the Mediterranean diet due to its high nutritional value. However, at the same time, because of economical purposes, it is also one of the products most subjected to adulteration. As a result, authenticity is an important issue of concern among authorities. Many analytical techniques, able to detect adulteration of olive oil, to identify its geographical and botanical origin and consequently guarantee its quality and authenticity, have been developed. This review paper discusses the use of infrared and Raman spectroscopy as candidate tools to examine the authenticity of olive oils. It also considers the volatile fraction as a marker to distinguish between different varieties and adulterated olive oils, using SPME combined with gas chromatography technique.

Highlights

According to the International Olive Council (IOC), olive oil can be defined as the product of the fruits from Olea europea L., trees obtained physically or mechanically by washing, decantation, centrifugation and filtration
Bendini et al (2007) [43] analyzed 84 samples of Extra Virgin Olive Oil (EVOO) derived from different regions of Italy and classified them according to their geographical origin using Attenuated Total Reflection (ATR)-FTIR combined with Partial Least Square Regression analysis (PLS) and Principal Component analysis (PCA) analysis
Results showed that samples did not present significant differences regarding their qualitative profile; quantitative differences exist and helped differentiate Virgin Olive Oil (VOO) according to their geographical origin with Analysis of Variance (ANOVA), PCA and Hierarchical Cluster Analysis (HCA)

Summary

Introduction

According to the International Olive Council (IOC), olive oil can be defined as the product of the fruits from Olea europea L., trees obtained physically or mechanically by washing, decantation, centrifugation and filtration. (EEC) 2568/91) and IOC have introduced specific requirements, according to which olive oil is classified in different categories which (a) define its quality, namely: alkyl esters of fatty acids composition (which are constituents connected to quality decline when their estimated value is greater than those imposed by legislative authorities), degree of acidity (expressed as a percentage of g of oleic acid in 100 g of oil), determination of peroxides (expressed as milliequivalents of active oxygen per kilogram which oxidize potassium iodide), spectrophotometric indices and sensory characteristics (flavor and aroma) and (b) are characteristic parameters of its purity such as quantification of waxes (the limit is set at 150 mg/kg for EVOO and VOO), sterols (total sterol content (mg/kg) as well as % of free sterols), 2-glyceryl mono-palmitate [1] This classification includes Extra Virgin Olive Oil (EVOO), which is directly produced from olives using mechanical means. Articles regarding Infrared (IR) and Raman spectroscopy as well as gas chromatography (GC), able to detect adulteration and to classify EVOO and VOO according to their geographical and botanical origin, are presented by giving a brief summary of the vast available published information

Spectroscopic Techniques Used to Evaluate Adulteration of EVOO and VOO

Detection of EVOO and VOO Adulteration by Gas Chromatography

Method

Findings

Discussion

Conclusions