Complementary Use of Multi-dimensional Gas Chromatography and Proton Transfer Reaction Mass Spectrometry for Identification of Rapeseed Oil Quality Indicators

Tomasz Majchrzak,Jacek Namieśnik,Wojciech Wojnowski,Tomasz Dymerski,Jacek Gębicki

doi:10.1007/s12161-018-1318-7

Tomasz Majchrzak, Jacek Namieśnik + Show 3 more

Open Access

https://doi.org/10.1007/s12161-018-1318-7

Copy DOI

Journal: Food analytical methods	Publication Date: Jul 7, 2018
Citations: 7	License type: open-access

Affiliation: Gdańsk University of Technology

Abstract

The change of concentration of various volatiles generated during frying may be an indicator of oil quality. Chemical compounds such as aldehydes, ketones, alcohols and carboxyl acids are the products of oxidation during thermal degradation of edible oils. Shown in this work is a complementary use of GC×GC-TOFMS and PTR-MS for the detection and determination of quality indicators of rapeseed oil. The former technique was used for the identification of potential markers and the latter for their quantitative determination. As a result of the GC×GC analysis, it was determined that 2-pentanone, heptane, octane, 1-heptanol and nonanal can be considered indicators of thermal degradation of rapeseed oil. Using PTR-MS, it was possible to monitor the concentration of these volatile indicators in real time. Based on the results of the analysis and of the reference method, it was concluded that 1-heptanol is best suited for the role of a quality indicator of thermal degradation of rapeseed oil.

Highlights

Frying is one of the basic methods of food processing
Due to the complex matrix composition and screening character of the measurement, a relatively universal CAR/DVB/ PDMS SPME fibre was chosen for the Gas chromatography (GC)×GC analysis
Based on the headspace analysis, it was possible to tentatively identify from over 200 volatile chemical compounds in samples incubated at 20 °C to app. 400 volatiles in the headspace of rapeseed oil incubated at 180 °C

Summary

Introduction

Frying is one of the basic methods of food processing. It contributes to the flavour, aroma, colour and texture of food products (Bordin et al 2013) and is a staple of many cuisines. During thermal degradation of edible oils, compounds such as carboxylic acids, carbohydrates, ketones, esters, lactones or aldehydes are generated. Some of these compounds, e.g. aldehydes, are volatile products of edible oils’ oxidation (Fullana et al 2004). Hexanal is recognised as an indicator of the degree of oxidation of rapeseed oil (Matthäus 2006). Methods such as sensory analysis (IOC 2005), determination of peroxide value (in autooxidation process)

Methods

Results

Conclusion