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Threonine aldolase and alcohol dehydrogenase activities in Lactobacillus bulgaricus and Lactobacillus acidophilus and their contribution to flavour production in fermented milks

Published online by Cambridge University Press:  01 June 2009

Valerie M. Marshall
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading RG2 9 AT, UK
Wendy M. Cole
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading RG2 9 AT, UK

Summary

Cell-free extracts of both Lactobacillus bulgaricus and L. acidophilus demonstrated threonine aldolase activity, the end product of which was acetaldehyde, the major flavour compound of yoghurt. L. acidophilus also possessed an alcohol dehydrogenase activity capable of reducing acetaldehyde so that little yoghurt flavour was present in milks fermentation with this organism. Addition of threonine to fortified milk before fermentation with L. acidophilus increased acetaldehyde production and resulted in a well flavoured product similar to that of yoghurt made with L. bulgaricus. The contribution of these 2 enzymes to flavour production is discussed.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1983

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References

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