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
- 1k Downloads
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 (C2H 4 + ) produced by charge transfer from residual O 2 + 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.
KeywordsPTR-ToF-MS Volatile compounds Apple (Malus × domestica) Climacteric post-harvest ripening
- Brackmann, A., Streif, J., & Bangerth, F. (1993). Relationship between a reduced aroma production and lipid metabolism of apples after long-term controlled atmosphere storage. Journal of American Society of Horticulture Science, 118, 243–247.Google Scholar
- Cappellin, L., Karl, T., Probst, M., Ismailova, O., Winkler, P. M., Soukoulis, C., et al. (2012). On quantitative determination of volatile organic compound concentrations using proton transfer reaction time-of-flight mass spectrometry. Enviromental Science Technology. doi: 10.1021/es203985t. In press.
- Cappellin, L., Probst, M., Limtrakul, J., Biasioli, F., Schuhfried, E., Soukoulis, C., et al. (2010). Proton transfer reaction rate coefficients between H3O + and some sulphur compounds. International Journal of Mass Spectrometry, 295(1–2), 45–48.Google Scholar
- de Vries, H. S. M., Wason, M. A. J., Harren, F. J. M., Woltering, E. J., van der Valk, H. C. P. M., & Reuss, J. (1996). Ethylene and CO2 emission rates and pathways in harvested fruits investigated, in situ, by laser photo deflection and photoacoustic techniques. Postharvest Biology and Technology, 8, 1–10.CrossRefGoogle Scholar
- Dunemann, F., Ulrich, D., Malysheva-Otto, L., Weber, W. E., Longhi, S., Velasco, R., et al. (2012). Functional allelic diversity of the apple alcohol acyl-transferase gene MdAAT1 associated with fruit ester volatile contents in apple cultivars. Molecular Breeding, 29, 609–6250.CrossRefGoogle Scholar
- Fabris, A., Biasioli, F., Granitto, P., Aprea, E., Cappellin, L., Schuhfried, E., et al. (2010). PTR-TOF-MS and data mining methods for rapid characterization of agro-industrial samples: Influence of milk storage conditions on the volatile profile of Trentingrana cheese. Journal of Mass Spectrometry, 45, 1065–1074.CrossRefGoogle Scholar
- Fellman, J. K., Miller, T. W., Mattinson, D. S., & Mattheis, J. P. (2000). Factors that influence biosynthesis of volatile flavor compounds in apple fruits. Hortscience, 35, 1026–1032.Google Scholar
- Harren, F. J. M., Cotti, G., Oomens, J. L., & Hekkert, S. (2006). Photoacoustic spectroscopy in trace gas monitoring. In R. A. Meyers (Ed.), Encyclopaedia of analytical chemistry. Chichester: Wiley.Google Scholar
- Jordan, A., Haidacher, S., Hanel, G., Hartungen, E., Herbig, J., & Märk, L. (2009). An online ultra-high sensitivity proton-transfer-reaction mass-spectrometer combined with switchable reagent ion capability (PTR + SRI − MS). International Journal of Mass Spectrometry, 286, 32–38.CrossRefGoogle Scholar
- Lang, & Hübert, T. (in press). A colour ripeness indicator for apples. Food Bioprocess and Technology. doi: 10.1007/s11947-011-0694-4.
- Mattheis, J. P., Buchanan, D. A., & Fellman, J. K. (1998). Volatile compounds emitted by ‘Gala’ apples following dynamic atmosphere storage. Journal of American Society of Horticulture Science, 123, 426–432.Google Scholar
- Onishi, M., Inoue, M., Araki, T., Iwabuchi. H., Sagara, Y. (in press). A PTR-MS-based protocol for simulating bread aroma during mastication. Food Bioprocess and Technology. doi: 10.1007/s11947-010-0422-5.
- Schaffer, R. J., Friel, E. N., Souleyre, E. J. F., Bolitho, K., Thodey, K., Ledger, S., et al. (2007). A genomics approach reveals that aroma production in apple is controlled by ethylene predominantly at the final step in each biosynthetic pathway. Plant Physiology, 144, 1899–1912.CrossRefGoogle Scholar
- Soukoulis, C., Aprea. E., Biasioli, F., Cappellin, L., Schuhfried, E., Märk, T.D., et al. (in press). PTR-TOF-MS analysis for influence of milk base supplementation on texture and headspace concentration of endogenous volatile compounds in yogurt. Food Bioprocess and Technology. doi: 10.1007/s11947-010-0487-1.