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Int J Mol Sci

Title:		"Effect of Co-Inoculation with Saccharomyces cerevisiae and Lactic Acid Bacteria on the Content of Propan-2-ol, Acetaldehyde and Weak Acids in Fermented Distillery Mashes"
Author(s):		Pielech-Przybylska K; Balcerek M; Ciepielowski G; Pacholczyk-Sienicka B; Albrecht L; Dziekonska-Kubczak U; Bonikowski R; Patelski P;
Address:		"Department of Spirit and Yeast Technology, Institute of Fermentation Technology and Microbiology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. katarzyna.pielech-przybylska@p.lodz.pl. Department of Spirit and Yeast Technology, Institute of Fermentation Technology and Microbiology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. maria.balcerek@p.lodz.pl. Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland. grzegorz.ciepielowski@p.lodz.pl. Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland. barbara.pacholczyk@p.lodz.pl. Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland. lukasz.albrecht@p.lodz.pl. Department of Spirit and Yeast Technology, Institute of Fermentation Technology and Microbiology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. urszula.dziekonska-kubczak@p.lodz.pl. Institute of General Food Chemistry, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Lodz, Poland. radoslaw.bonikowski@p.lodz.pl. Department of Spirit and Yeast Technology, Institute of Fermentation Technology and Microbiology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. piotr.patelski@p.lodz.pl"
Journal Title:		Int J Mol Sci
Year:		2019
Volume:		20190403
Issue:		7
Page Number:		-
DOI:		10.3390/ijms20071659
ISSN/ISBN:		1422-0067 (Electronic) 1422-0067 (Linking)
Abstract:		"The qualitative and quantitative composition of volatile compounds in fermented distillery mash determines the quality of the obtained distillate of agricultural origin (i.e., raw spirit) and the effectiveness of further purification steps. Propan-2-ol (syn. isopropyl alcohol), due to its low boiling point, is difficult to remove by rectification. Therefore, its synthesis needs to be limited during fermentation by Saccharomyces cerevisiae yeast, while at the same time controlling the levels of acetaldehyde and acetic acid, which are likewise known to determine the quality of raw spirit. Lactic acid bacteria (LAB) are a common but undesirable contaminant in distillery mashes. They are responsible for the production of undesirable compounds, which can affect synthesis of propan-2-ol. Some bacteria strains are able to synthesize isopropyl alcohol. This study therefore set out to investigate whether LAB with S. cerevisiae yeast are responsible for conversion of acetone to propan-2-ol, as well as the effects of the amount of LAB inoculum and fermentation parameters (pH and temperature) on the content of isopropyl alcohol, acetaldehyde, lactic acid and acetic acid in fermented mashes. The results of NMR and comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (GC x GC-TOF MS) analysis confirmed the ability of the yeast and LAB strains to metabolize acetone via its reduction to isopropyl alcohol. Efficient fermentation of distillery mashes was observed in all tested mashes with an initial LAB count of 3.34-6.34 log cfu/mL, which had no significant effect on the ethanol content. However, changes were observed in the contents of by-products. Lowering the initial pH of the mashes to 4.5, without and with LAB (3.34-4.34 log cfu/mL), resulted in a decrease in propan-2-ol and a concomitant increase in acetaldehyde content, while a higher pH (5.0 and 5.5) increased the content of propan-2-ol and decreased acetaldehyde content. Higher temperature (35 degrees C) promoted propan-2-ol synthesis and also resulted in increased acetic acid content in the fermented mashes compared to the controls. Moreover, the acetic acid content rose with increases in the initial pH and the initial LAB count"
Keywords:		2-Propanol/*metabolism Acetaldehyde/*metabolism Acetic Acid/metabolism Acetone/metabolism Carbon Isotopes/chemistry *Distillation *Fermentation Lactic Acid/metabolism Lactobacillales/*metabolism Proton Magnetic Resonance Spectroscopy Saccharomyces cerevis;
Notes:		"MedlinePielech-Przybylska, Katarzyna Balcerek, Maria Ciepielowski, Grzegorz Pacholczyk-Sienicka, Barbara Albrecht, Lukasz Dziekonska-Kubczak, Urszula Bonikowski, Radoslaw Patelski, Piotr eng PBS2/B8/9/2013/Narodowe Centrum Badan i Rozwoju/ Switzerland 2019/04/17 Int J Mol Sci. 2019 Apr 3; 20(7):1659. doi: 10.3390/ijms20071659"