Determination of Triacylglycerols by HTGC-FID as a Sensitive Tool for the Identification of Rapeseed and Olive Oil Adulteration.

Ying Qian,Magdalena Rudzińska,Anna Grygier,Roman Przybylski

doi:10.3390/molecules25173881

Ying Qian, Magdalena Rudzińska + Show 2 more

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https://doi.org/10.3390/molecules25173881

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Abstract

Triacylglycerols (TGs) are the most common compounds in food lipids, accounting for 95% of the weight of edible oils. The aim of this study was to scrutinize a procedure for quantitatively assessing possible adulteration of olive and rapeseed oil through GC-FID analysis of TGs. The recovery of TG standards ranged from 21% to 148%, and the relative response factor (RRF) ranged from 0.42 to 2.28. The limits of detection were in the range of 0.001 to 0.330 µg/mL, and the limits of quantitation from 0.001 to 1.000 µg/mL. The validated method was used to determine the TGs in olive oil (OO), refined rapeseed oil (RRO), and their blends. Eight TGs were detected in refined rapeseed oil, and 10 in olive oil. The addition of 1% of olive oil to rapeseed oil or vice versa can be detected using this method. Three triacylglycerols were pinpointed as indicators of adulteration of rapeseed oil with olive oil (PPO, PPL, PSO). The method described here can be used for controlling the quality of these oils.

Highlights

Triacylglycerols (TGs) are the most common compounds in food lipids, accounting for more than95% of the weight of edible oils
The equivalent of carbon number (ECN) was calculated by the relation ECN = CN-2 × double bonds number (DB), where CN is a carbon number and DB is the number of double bonds [13]; this ranged from 42 to 57
Refined olive pomace oil produced by Primadonna (Poland) and refined rapeseed oil produced by ZT Kruszwica (Warsaw, Poland) were purchased from a supermarket in Poland

Summary

Introduction

Triacylglycerols (TGs) are the most common compounds in food lipids, accounting for more than. 95% of the weight of edible oils. The glycerol molecule is esterified with three fatty acids (Figure 1), monoglycerols and diacylglycerols may be present. The monoesters and diesters are often used in food applications as additives and emulsifiers. The TG composition of edible oils is rather difficult to analyze, due to its complexity, with vegetable oils containing a wide range of different fatty acids (FAs). Such analysis is possible for mixtures of TGs with similar molecular weights but different molecular structures, due to the three possible positions of the fatty acid on the glycerol molecule.

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