Characterization of Volatile Organic Compounds in ‘Rossa di Tropea’ Onion by Means of Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS/SPME GC–MS) and Sensory Analysis

Abstract

Background: Plant viral infections induce changes in the host plant, which can potentially impact composition, organoleptic properties, and storability characteristics of plant products. In particular, onion odor and flavor are determined mainly by volatile organic compounds, and changes upon infection with onion yellow dwarf virus may deeply influence these characters. Methods: A time-course study of volatile organic compounds in onion yellow dwarf virus-infected versus healthy ‘Rossa di Tropea’ onion bulbs was performed using headspace solid-phase microextraction gas chromatography–mass spectrometry; sensory analysis performed at marketability stage of onion production was used to correlate such changes to the taste characteristics perceived by consumers. Results: Volatile organic compounds regulated in infection conditions were identified, mainly belonging to mono- and poly-sulfides classes. The most abundant compounds in the analyzed samples were propyl disulfide, allyl-isopropyl disulfide, and propanethiol; significantly different concentrations were observed for 7 out of 11 VOCs in virus-infected compared to healthy bulbs. Statistical analysis based on a partial least squares discriminant analysis model and hierarchical cluster analysis allowed us to cluster samples based on phytosanitary status and storage time and to identify the most responsible compounds for such classification. Conclusions: Onion yellow dwarf virus infection induces changes in volatile organic compounds in onion during storage. The impact of such regulated compounds on ‘Rossa di Tropea’ onion odor and flavor and correlation with sensory analysis are discussed.

Application of Direct Thermal Desorption–Gas Chromatography–Mass Spectrometry for Determination of Volatile and Semi-Volatile Organosulfur Compounds in Onions: A Novel Analytical Approach

“…The resulting mixture of monosulfides, disulfides, and trisulfides accounted for 4.9%, 23.9%, and 9.6% (i.e., 38.4% of carbon sulfide CS n ) of the red onion composition, respectively. Additionally, propanothiol was identified as a significant source of flavor in fresh onions [ 41 ], accounting for 5.9% of the red onion composition.…”

Latest Improvements and Expanding Applications of Solid-Phase Microextraction

“…A large number of plants own distinctive odors. Analyzing these odors is expected to reveal unique biomarkers for species identification and provide important data for economic valuation. − HS-SPME is an excellent candidate for odor enrichment, and the mixed fibers including DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB are preferred due to the synergetic effects of absorbents and adsorbents. − It is worth mentioning that the hybrid composites of silica aerogel, preyssler-type polyoxometalate, and MIL-101­(Cr) have been fabricated as a highly porous fiber coating, which has been successfully used for the headspace extraction and identification of Ferulago angulata volatile components. Exerting a magnetic field on the prepared SPME fiber using a permanent magnet substantially improves the extraction efficiency for the volatile components, to an average of 73% …”

Conservation and Global Distribution of Onion (Allium cepa L.) Germplasm for Agricultural Sustainability

“…With a long and varied history, onion is believed to be among the first plant species to be domesticated during the era of ancient human civilization [ 8 , 9 ]. For instance, archaeological evidence suggests that onion domestication took place over 4000 years ago [ 10 , 11 , 12 ]. The domestication process, like in many other crop species, involved cultivating wild onion species and selecting specific genotypes based on desirable characteristics determined by early growers [ 3 ].…”