PTR-ToF-MS, A Novel, Rapid, High Sensitivity and Non-Invasive Tool to Monitor Volatile Compound Release During Fruit Post-Harvest Storage: The Case Study of Apple Ripening

In the present study, the potential of PTR-ToF-MS for addressing fundamental and technical post-harvest issues was tested on the non-destructive and rapid monitoring of volatile compound evolution in three apple cultivars (‘Golden Delicious’, ‘Braeburn’ and ‘Gold Rush’) during 25 days of post-harvest shelf life ripening. There were more than 800 peaks in the PTR-ToF-MS spectra of apple headspace and many of them were associated with relevant compounds. Besides the ion produced upon proton transfer, we used the ion at mass 28.031 (C2H4+) produced by charge transfer from residual O2+ as a monitor for ethylene concentration. ‘Golden Delicious’ apples were characterised by higher ethylene emission rates than ‘Gold Rush’ and ‘Braeburn’, and quantitative comparison has been supported by two segment piecewise linear model fitting. Ester evolution during post-harvest ripening is strongly dependent on endogenous ethylene concentration levels. For ‘Golden Delicious’ and ‘Braeburn’, sesquiterpenes (alpha-farnesene) exhibited a fast response to ethylene emission followed by a rapid decline after the endogenous ethylene maximum peak. Carbonyl compounds displayed a different time evolution as compared to esters and terpenes and did not show any evident relationship with ethylene. Methanol and ethanol concentrations during the entire storage period did not change significantly. We show how multivariate analysis can efficiently handle the large datasets produced by PTR-ToF-MS and that the outcomes obtained are in agreement with the literature. The different volatile compounds could be simultaneously monitored with high time resolution, providing advantages over the more established techniques for the investigation of VOC dynamics in fruit post-harvest storage trials.

[1]  P. Monks,et al.  Proton-Transfer Reaction Mass Spectrometry , 2009 .

[2]  Franco Biasioli,et al.  Direct-injection mass spectrometry adds the time dimension to (B)VOC analysis , 2011 .

[3]  Z. Ju,et al.  Evidence that α-farnesene biosynthesis during fruit ripening is mediated by ethylene regulated gene expression in apples , 2000 .

[4]  G. Echeverría,et al.  Volatile production, quality and aroma-related enzyme activities during maturation of ‘Fuji’ apples , 2004 .

[5]  J. M. Allen,et al.  Biosynthesis of straight-chain ester volatiles in red delicious and granny smith apples using deuterium-labeled precursors. , 1999, Journal of agricultural and food chemistry.

[6]  S. Inomata,et al.  Development of a PTR-TOFMS instrument for real-time measurements of volatile organic compounds in air , 2007 .

[7]  Philipp Sulzer,et al.  A high resolution and high sensitivity proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) , 2009 .

[8]  S. Wyllie,et al.  Relationship between production of ethylene and α-farnesene in apples, and how it is influenced by the timing of diphenylamine treatment , 2001 .

[9]  Errol W. Hewett,et al.  Factors affecting apple aroma/flavour volatile concentration: A Review , 2000 .

[10]  C. Delahunty,et al.  Analysis of volatile flavour compounds by Proton Transfer Reaction-Mass Spectrometry: fragmentation patterns and discrimination between isobaric and isomeric compounds , 2002 .

[11]  Franco Biasioli,et al.  PTR-TOF-MS and data-mining methods for rapid characterisation of agro-industrial samples: influence of milk storage conditions on the volatile compounds profile of Trentingrana cheese. , 2010, Journal of mass spectrometry : JMS.

[12]  James P. Mattheis,et al.  Factors that Influence Biosynthesis of Volatile Flavor Compounds in Apple Fruits , 1997 .

[13]  Abhaya M Dandekar,et al.  Relationship of ethylene biosynthesis to volatile production, related enzymes, and precursor availability in apple peel and flesh tissues. , 2005, Journal of agricultural and food chemistry.

[14]  Philipp Sulzer,et al.  An online ultra-high sensitivity Proton-transfer-reaction mass-spectrometer combined with switchable reagent ion capability (PTR + SRI − MS) , 2009 .

[15]  Pablo M. Granitto,et al.  On data analysis in PTR-TOF-MS: From raw spectra to data mining , 2011 .

[16]  A. Dandekar,et al.  Impact of suppression of ethylene action or biosynthesis on flavor metabolites in apple (Malus domestica Borkh) fruits. , 2004, Journal of agricultural and food chemistry.

[17]  F. Biasioli,et al.  PTR-MS real time monitoring of the emission of volatile organic compounds during postharvest aging of berryfruit , 1999 .

[18]  J. Giovannoni,et al.  MOLECULAR BIOLOGY OF FRUIT MATURATION AND RIPENING. , 2001, Annual review of plant physiology and plant molecular biology.

[19]  P. White.  Recent advances in fruit development and ripening: an overview. , 2002, Journal of experimental botany.

[20]  F. Bangerth,et al.  Fatty acids as precursors for aroma volatile biosynthesis in pre-climacteric and climacteric apple fruit , 2003 .

[21]  Robert J. Schaffer,et al.  A Genomics Approach Reveals That Aroma Production in Apple Is Controlled by Ethylene Predominantly at the Final Step in Each Biosynthetic Pathway[W] , 2007, Plant Physiology.

[22]  W. B. Knighton,et al.  HCN detection with a proton transfer reaction mass spectrometer , 2009 .

[23]  Franco Biasioli,et al.  Fingerprinting mass spectrometry by PTR-MS: heat treatment vs. pressure treatment of red orange juice—a case study , 2003 .

[24]  Y. Sagara,et al.  A PTR-MS-Based Protocol for Simulating Bread Aroma During Mastication , 2012, Food and Bioprocess Technology.

[25]  J. C. Reynolds,et al.  A hollow cathode proton transfer reaction time of flight mass spectrometer , 2005 .

[26]  S. Cristescu,et al.  Photoacoustic Spectroscopy in Trace Gas Monitoring , 2000, Encyclopedia of Analytical Chemistry.

[27]  Xuewen Lu,et al.  Ester variability in apple varieties as determined by solid-phase microextraction and gas chromatography-mass spectrometry. , 2004, Journal of agricultural and food chemistry.

[28]  J. Fellman,et al.  Volatile Compounds Emitted by `Gala' Apples following Dynamic Atmosphere Storage , 1998 .

[29]  R. Baraldi,et al.  Seasonal variation of monoterpene emission from Malus domestica and Prunus avium. , 2001, Phytochemistry.

[30]  F. Bangerth,et al.  Relationship between a reduced aroma production and lipid metabolism of apples after long-term controlled-atmosphere storage , 1993 .

[31]  F. Biasioli,et al.  On quantitative determination of volatile organic compound concentrations using proton transfer reaction time-of-flight mass spectrometry. , 2012, Environmental science & technology.

[32]  T. Hübert,et al.  A Colour Ripeness Indicator for Apples , 2012, Food and Bioprocess Technology.

[33]  C. N. Hewitt,et al.  Measurement of monoterpenes and related compounds by proton transfer reaction-mass spectrometry (PTR-MS) , 2003 .

[34]  F. Biasioli,et al.  Effects of supercritical CO2 and N2O pasteurisation on the quality of fresh apple juice , 2009 .

[35]  Robert J. Schaffer,et al.  Co-ordination of early and late ripening events in apples is regulated through differential sensitivities to ethylene , 2009, Journal of experimental botany.

[36]  F. Biasioli,et al.  PTR-TOF-MS Analysis for Influence of Milk Base Supplementation on Texture and Headspace Concentration of Endogenous Volatile Compounds in Yogurt , 2012, Food and Bioprocess Technology.

[37]  Bruce D. Whitaker,et al.  Cloning and functional expression of an (E,E)-α-farnesene synthase cDNA from peel tissue of apple fruit , 2004, Planta.

[38]  F. Biasioli,et al.  PTR-MS measurements and analysis of models for the calculation of Henry's law constants of monosulfides and disulfides. , 2011, Chemosphere.

[39]  F. Biasioli,et al.  PTR-MS study of esters in water and water/ethanol solutions: Fragmentation patterns and partition coefficients , 2007 .

[40]  Mondher Bouzayen,et al.  Ethylene and fruit ripening , 1997 .

[41]  F. Biasioli,et al.  Proton transfer reaction rate coefficients between H3O+ and some sulphur compounds , 2010 .

[42]  A. Hansel,et al.  On-line monitoring of volatile organic compounds at pptv levels by means of proton-transfer-reaction mass spectrometry (PTR-MS) medical applications, food control and environmental research , 1998 .

[43]  W. Weg,et al.  Role of the genes Md-ACO1 and Md-ACS1 in ethylene production and shelf life of apple (Malus domestica Borkh) , 2005, Euphytica.

[44]  W. E. van de Weg,et al.  QTL dynamics for fruit firmness and softening around an ethylene-dependent polygalacturonase gene in apple (Malus×domestica Borkh.) , 2010, Journal of experimental botany.

[45]  G. Echeverría,et al.  Multivariate analysis of modifications in biosynthesis of volatile compounds after CA storage of 'Fuji' apples , 2006 .

[46]  Jun Song,et al.  Flavour volatile production and regulation in fruit , 2008 .

[47]  C. Furlanello,et al.  Rapid and non-destructive identification of strawberry cultivars by direct PTR-MS headspace analysis and data mining techniques , 2007 .

[48]  Fritz Bangerth,et al.  The effect of harvest date on aroma compound production from ‘Golden Delicious’ apple fruit and relationship to respiration and ethylene production , 1996 .

[49]  F. Biasioli,et al.  PTR-MS monitoring of VOCs and BVOCs in food science and technology , 2011 .

[50]  J. Reuss,et al.  Ethylene and CO2 emission rates and pathways in harvested fruits investigated, in situ, by laser photothermal deflection and photoacoustic techniques , 1996 .

[51]  A. Bleecker,et al.  Ethylene: a gaseous signal molecule in plants. , 2000, Annual review of cell and developmental biology.

[52]  F. Biasioli,et al.  QTL mapping of volatile compounds in ripe apples detected by proton transfer reaction-mass spectrometry , 2005, Euphytica.

[53]  Functional allelic diversity of the apple alcohol acyl-transferase gene MdAAT1 associated with fruit ester volatile contents in apple cultivars , 2012, Molecular Breeding.

[54]  Takeo Harada,et al.  Null Mutation of the MdACS3 Gene, Coding for a Ripening-Specific 1-Aminocyclopropane-1-Carboxylate Synthase, Leads to Long Shelf Life in Apple Fruit1[W][OA] , 2009, Plant Physiology.

[55]  B. Barritt,et al.  Md-ACS1 and Md-ACO1 genotyping of apple (Malus x domestica Borkh.) breeding parents and suitability for marker-assisted selection , 2008, Tree Genetics & Genomes.