Microbes Influence Flavor in Kefir

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Washington, D.C.— The American Society of Microbiology published a study in mSystems on October 4, 2016, by the APC Microbiome Institute, in which they sequenced and anaylyzed the changes of microbial populations in three different kefirs from distinct geographic locations over 24 hours of fermentation. Analysis showed that Lactobacillus kefiranofaciens was the dominant bacteria early in the fermentation process at eight hours but between eight and 24 hours, it decreased and Leuconostoc mesenteroides increased, becoming at least 1/3 of the bacterial population. This same period saw an increased abundance of Acetobacter pasteurianus, Lactobacillus helveticus, Leuconostoc citreum, Leuconostoc gelidum and Leuconostoc kimchii.

Besides sequencing the microbial populations over time, the researchers also found a relationship between the abundance of particular microbial genera and species with different volatile compounds that influence flavor. For example, “L. kefiranofaciens correlated with carboxylic acids and ketones associated with cheesy flavors and with esters associated with fruity flavors,” while “Acetobacter pasteurianus correlated with acetic acid, which is associated with vinegary flavors.”

These results are valuable considering the popularity of fermented foods and kefir’s role in that trend. “Ultimately, in addition to providing an important fundamental insight into microbial interactions, this information can be applied to optimize the fermentation processes, flavors, and health-related attributes of this and other fermented foods,” conclude the researchers.

Published in WholeFoods Magazine November 2016