title: Real-Time Mass Spectrometry Monitoring of Oak Wood Toasting: Elucidating Aroma Development Relevant to Oak-aged Wine Quality.
abstract: We introduce a real-time method to monitor the evolution of oak aromas during the oak toasting process. French and American oak wood boards were toasted in an oven at three different temperatures, while the process-gas was continuously transferred to the inlet of a proton-transfer-reaction time-of-flight mass spectrometer for online monitoring. Oak wood aroma compounds important for their sensory contribution to oak-aged wine were tentatively identified based on soft ionization and molecular mass. The time-intensity profiles revealed toasting process dynamics illustrating in real-time how different compounds evolve from the oak wood during toasting. Sufficient sensitivity was achieved to observe spikes in volatile concentrations related to cracking phenomena on the oak wood surface. The polysaccharide-derived compounds exhibited similar profiles; whilst for lignin-derived compounds eugenol formation differed from that of vanillin and guaiacol at lower toasting temperatures. Significant generation of oak lactone from precursors was evident at 225 (o)C. Statistical processing of the real-time aroma data showed similarities and differences between individual oak boards and oak wood sourced from the different origins. This study enriches our understanding of the oak toasting process and demonstrates a new analytical approach for research on wood volatiles.
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Ross R
authors.initials: RR
authors.lastname: Farrell
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, 8820 Wädenswil, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Wellinger
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, 8820 Wädenswil, Switzerland.
authors.forename: Alexia N
authors.initials: AN
authors.lastname: Gloess
authors.affiliation: Central Science Laboratory, University of Tasmania, Private Bag 74, Hobart, Tasmania 7001, Australia.
authors.forename: David S
authors.initials: DS
authors.lastname: Nichols
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Breadmore
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Shellie
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, 8820 Wädenswil, Switzerland.
authors.forename: Chahan
authors.initials: C
authors.lastname: Yeretzian
mesh_terms: D001547:Benzaldehydes / Q000302:isolation & purification; D005054:Eugenol / Q000302:isolation & purification; D019649:Food Industry / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006139:Guaiacol / Q000302:isolation & purification; D006358:Hot Temperature; D006801:Humans; D007783:Lactones / Q000302:isolation & purification; D008031:Lignin / Q000302:isolation & purification; D009812:Odorants / Q000032:analysis*; D029963:Quercus / Q000737:chemistry*; D012903:Smell / Q000502:physiology; D052616:Solid Phase Extraction; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000302:isolation & purification; D014920:Wine / Q000032:analysis*; D014934:Wood / Q000737:chemistry*
chemical_list: D001547:Benzaldehydes; D007783:Lactones; D055549:Volatile Organic Compounds; D005054:Eugenol; D006139:Guaiacol; D008031:Lignin; C100058:vanillin