Aromatic and proteomic analyses corroborate the distinction between Mediterranean landraces and modern varieties of durum wheat.

Federico Vita,Cosimo Taiti,Giuseppe Di Miceli,Larisa Whitney,Paolo Ruisi,Dario Giambalvo,Michele Monti,Emilio Lo Presti,Antonio Pompeiano,Zuguang Gu,Lorenzo Guglielminetti,Stefano Mancuso

doi:10.1038/srep34619

Abstract

In this paper volatile organic compounds (VOCs) from durum wheat cultivars and landraces were analyzed using PTR-TOF-MS. The aim was to characterize the VOC’s profile of the wholemeal flour and of the kernel to find out if any VOCs were specific to varieties and sample matrices. The VOC data is accompanied by SDS-PAGE analyses of the storage proteins (gliadins and glutenins). Statistical analyses was carried out both on the signals obtained by MS and on the protein profiles. The difference between the VOC profile of two cultivars or two preparations of the same sample - matrices, in this case kernel vs wholemeal flour - can be very subtle; the high resolution of PTR-TOF-MS - down to levels as low as pptv - made it possible to recognize these differences. The effects of grinding on the VOC profiles were analyzed using SIMPER and Tanglegram statistical methods. Our results show that it is possible describe samples using VOC profiles and protein data.

Highlights

1950 and for the quarter century or so, new mutagenesis[5] and crossing techniques were added to the effort to obtain cultivars with improved yield (‘intermediate’ cultivars)
Volatile organic compound (VOC) analysis in wheat can be done - for example - via gas chromatography-mass spectrometry (GC-MS) coupled with suitable techniques to concentrate volatiles such as dynamic headspace extraction[33] or via the headspace solid-phase microextraction[29] (HS-SPME)
To carry on from these initial works, we present for the first time the combined analyses of storage proteins and volatile organic compounds by SDS-PAGE and PTR-TOF analysis respectively, of Triticum wheat kernels and wholemeal flour, obtained from 47 landraces and varieties

Summary

Introduction

1950 and for the quarter century or so, new mutagenesis[5] and crossing techniques were added to the effort to obtain cultivars with improved yield (‘intermediate’ cultivars). The benefits of using GC-MS based methods rather than other analytical systems have been investigated One such other system is the “Proton Transfer Reaction-Mass Spectrometer (PTR-MS)”, a soft chemical ionization procedure that allows real time visualization of the flow of VOCs contemporary to the moment their signal is picked up by the detector present in the instrument. This allows for the elimination of the inconvenient delay associated with mass spectrometry/gas chromatography dependent methods, allowing for a massive increase in through-put potentiality. The kernel storage proteins (gliadins, glutenins) were analyzed by SDS-PAGE in order to complete the description of the samples

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