title: Proton-transfer-reaction mass spectrometry for the study of the production of volatile compounds by bakery yeast starters.
abstract: The aromatic impact of bakery yeast starters is currently receiving considerable attention. The flavor characteristics of the dough and the finished products are usually evaluated by gas chromatography and sensory analysis. The limit of both techniques resides in their low-throughput character. In the present work, proton-transfer-reaction mass spectrometry (PTR-MS), coupled to a time-of-flight mass analyzer, was employed, for the first time, to measure the volatile fractions of dough and bread, and to monitor Saccharomyces cerevisiae volatile production in a fermented food matrix. Leavening was performed on small-scale (1 g) dough samples inoculated with different commercial yeast strains. The leavened doughs were then baked, and volatile profiles were determined during leavening and after baking. The experimental setup included a multifunctional autosampler, which permitted the follow-up of the leavening process on a small scale with a typical throughput of 500 distinct data points in 16 h. The system allowed to pinpoint differences between starter yeast strains in terms of volatile emission kinetics, with repercussions on the final product (i.e. the corresponding micro-loaves). This work demonstrates the applicability of PTR-MS for the study of volatile organic compound production during bread-making, for the automated and online real-time monitoring of the leavening process, and for the characterization and selection of bakery yeast starters in view of their production of volatile compounds.
authors.affiliation: Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010, San Michele all'Adige, TN, Italy; Department of Chemistry, University of Balamand, P. O. Box 100, Tripoli, Lebanon; MR PAM-équipe VALMIS, IUVV, 1 rue Claude Ladrey, 21078, Dijon Cedex, France.
authors.forename: Salim
authors.initials: S
authors.lastname: Makhoul
authors.forename: Andrea
authors.initials: A
authors.lastname: Romano
authors.forename: Luca
authors.initials: L
authors.lastname: Cappellin
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Spano
authors.forename: Vittorio
authors.initials: V
authors.lastname: Capozzi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Benozzi
authors.forename: Tilmann D
authors.initials: TD
authors.lastname: Märk
authors.forename: Eugenio
authors.initials: E
authors.lastname: Aprea
authors.forename: Flavia
authors.initials: F
authors.lastname: Gasperi
authors.forename: Hanna
authors.initials: H
authors.lastname: El-Nakat
authors.forename: Jean
authors.initials: J
authors.lastname: Guzzo
authors.forename: Franco
authors.initials: F
authors.lastname: Biasioli
keywords: PTR-MS; VOCs; bakery; leavening; yeast