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Int J Food Microbiol

Title:		Influence of different proteolytic strains of Streptococcus thermophilus in co-culture with Lactobacillus delbrueckii subsp. bulgaricus on the metabolite profile of set-yoghurt
Author(s):		Settachaimongkon S; Nout MJ; Antunes Fernandes EC; Hettinga KA; Vervoort JM; van Hooijdonk TC; Zwietering MH; Smid EJ; van Valenberg HJ;
Address:		"Dairy Science and Technology Group, Chair of Food Quality and Design, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands. Laboratory of Food Microbiology, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands. Dairy Science and Technology Group, Chair of Food Quality and Design, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands. Laboratory of Biochemistry, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands. Dairy Science and Technology Group, Chair of Food Quality and Design, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands. Electronic address: hein.vanvalenberg@wur.nl"
Journal Title:		Int J Food Microbiol
Year:		2014
Volume:		20140221
Issue:
Page Number:		29 - 36
DOI:		10.1016/j.ijfoodmicro.2014.02.008
ISSN/ISBN:		1879-3460 (Electronic) 0168-1605 (Linking)
Abstract:		"Proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus is one of the key factors that determine the fermentation process and final quality of yoghurt. In this study, the interaction between different proteolytic strains of S. thermophilus and L. delbrueckii subsp. bulgaricus was investigated in terms of microbial growth, acidification and changes in the biochemical composition of milk during set-yoghurt fermentation. A complementary metabolomics approach was applied for global characterization of volatile and non-volatile polar metabolite profiles of yoghurt associated with proteolytic activity of the individual strains in the starter cultures. The results demonstrated that only non-proteolytic S. thermophilus (Prt-) strain performed proto-cooperation with L. delbrueckii subsp. bulgaricus. The proto-cooperation resulted in significant higher populations of the two species, faster milk acidification, significant abundance of aroma volatiles and non-volatile metabolites desirable for a good organoleptic quality of yoghurt. Headspace SPME-GC/MS and (1)H NMR resulted in the identification of 35 volatiles and 43 non-volatile polar metabolites, respectively. Furthermore, multivariate statistical analysis allows discriminating set-yoghurts fermented by different types of starter cultures according to their metabolite profiles. Our finding underlines that selection of suitable strain combinations in yoghurt starters is important for achieving the best technological performance regarding the quality of product"
Keywords:		Animals Fermentation *Food Microbiology Gas Chromatography-Mass Spectrometry Hydrogen-Ion Concentration Lactobacillus delbrueckii/growth & development/metabolism/*physiology Magnetic Resonance Spectroscopy Metabolomics Milk/*chemistry Multivariate Analysi;
Notes:		"MedlineSettachaimongkon, Sarn Nout, M J Robert Antunes Fernandes, Elsa C Hettinga, Kasper A Vervoort, Jacques M van Hooijdonk, Toon C M Zwietering, Marcel H Smid, Eddy J van Valenberg, Hein J F eng Research Support, Non-U.S. Gov't Netherlands 2014/03/07 Int J Food Microbiol. 2014 May 2; 177:29-36. doi: 10.1016/j.ijfoodmicro.2014.02.008. Epub 2014 Feb 21"