An evaluation of kefir grain size with magnetic resonance imaging to observe the fermentation of milk

Spicer, A. ORCID: 0000-0003-3177-8539, Fairhurst, D.J. ORCID: 0000-0001-5311-0762, Newton, M.I. ORCID: 0000-0003-4231-1002 and Morris, R.H. ORCID: 0000-0001-5511-3457, 2019. An evaluation of kefir grain size with magnetic resonance imaging to observe the fermentation of milk. Magnetic Resonance in Chemistry, 57 (9): 730-737, pp. 730-737. ISSN 0749-1581

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Kefirian milk is a fermented beverage consumed worldwide. Originally produced in animal skins, it is now prepared both industrially and at home by adding symbiotic cultures of bacteria and yeast known as kefir grains to fresh milk. There is significant literature on the biological aspects of this process but little focus on the fermentation effects on the bulk milk as a function of the grain morphology. Changes in the MR signal as measured using a whole body clinical MRI scanner are found to be proportional to traditional gas measurements with correlation coefficients in excess of 0.95. Magnetic Resonance Imaging is then also used to determine the effect of grain size on the rate of fermentation of milk. It is found that larger grains result in signal intensity changes on the order of 0.03 a.u per hour but by breaking the grains into pieces around 3mm the reaction rate can be more than doubled to 0.07 a.u. per hour. It is thought that this shows promise as a method to improve the speed of production of Kefirian milk and by arresting the process partway through fermentation, gives control over the properties of the end product.

Item Type: Journal article
Publication Title: Magnetic Resonance in Chemistry
Creators: Spicer, A., Fairhurst, D.J., Newton, M.I. and Morris, R.H.
Date: September 2019
Volume: 57
Number: 9
ISSN: 0749-1581
Divisions: Schools > School of Science and Technology
Record created by: Jonathan Gallacher
Date Added: 05 Apr 2019 07:40
Last Modified: 25 Jun 2021 13:53

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