Impact of sourdough culture on the volatile compounds in wholemeal sourdough bread

• Published in: Food research international Vol. 161; p. 111885
• Main Authors: Warburton, Andrea, Silcock, Patrick, Eyres, Graham T.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2022
• Subjects: Fermentation; Gas chromatography mass spectrometry (GC-MS); Lactic acid bacteria; Proton transfer reaction mass spectrometry (PTR-MS); Sourdough bread; Volatile organic compounds; Yeast; Volatile organic compounds; Lactic acid bacteria; Yeast; Gas chromatography mass spectrometry (GC-MS); Sourdough bread; Fermentation; Proton transfer reaction mass spectrometry (PTR-MS)
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2022.111885

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•Dried sourdough cultures successfully produced complex sourdough breads that possessed a distinctive range of volatile compounds and concentrations.•Multiple Factor Analysis (MFA) effectively identified relationships between volatile compounds, physicochemical measures and starter culture in sourdough breads.•Variations in the inferred microbial composition of the dried sourdough cultures and fermentation activity led to differences in sourdough bread properties.
Sourdough bread has a complex flavour profile, which is strongly influenced by the compounds generated during fermentation by the diverse array of microorganisms present, mainly yeasts and lactic acid bacteria (LAB). Twelve complex sourdough cultures, comprised of mixtures of yeast and bacteria, were propagated using wholemeal flour and used in the production of sourdough breads. The volatile organic compounds (VOCs) present in the sourdough bread crumb were characterised by gas chromatography-mass spectrometry (GC-MS) and proton transfer reaction-mass spectrometry (PTR-MS). Multiple factor analysis (MFA) relating the VOCs and physicochemical features of the sourdough breads (pH, TTA, lactic acid, colour and size) identified three distinct clusters. Cluster 1 was distinguished by VOCs, such as ethanol, 3-methyl-1-butanol, phenylethanol, 2-methyl-1-propanol, acetaldehyde and 2,3-butanedione, along with size related measures and increased production of lactic acid, indicating that yeast activity and homofermentative or facultative heterofermentative LAB were dominant. In contrast, cluster 2 was associated with acetic acid and acetate esters along with acidity related measures indicating a dominance of obligate heterofermentative LAB. Cluster 3 was also related to yeast fermentation activity, but particularly fermentation of lipids with greater production of aldehydes and lactones. The distinct differences between clusters of sourdough breads in their volatile and non-volatile features could be attributed to their fermentation activity and whether the culture was dominated by yeast or the different classes of LAB.