RT Journal Article
SR Electronic
T1 Raw milk kefir: microbiota, bioactive peptides, and immune modulation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.10.19.512868
DO 10.1101/2022.10.19.512868
A1 Ton Baars
A1 Betty van Esch
A1 Luuk van Ooijen
A1 Zuomin Zhang
A1 Pieter Dekker
A1 Sjef Boeren
A1 Mara Diks
A1 Johan Garssen
A1 Kasper Hettinga
A1 Remco Kort
YR 2022
UL http://biorxiv.org/content/early/2022/10/25/2022.10.19.512868.abstract
AB This study aims to characterize the microbial and peptidomic composition of raw milk kefir, and to address the potential anti-allergic effects of raw milk kefir using validated research models for food allergy. Raw milk kefir was produced after incubation with a defined freeze-dried starter culture. Kefir was sampled during fermentation at seven-time intervals. For comparison, kefir was also prepared from boiled milk (100 °C; 5 sec). Peptide compositions were determined for the raw and heated milk, plus kefir end products made from these milks. In a murine food allergy model, the two kefir end products were investigated on their allergy modulating effects. In both kefirs, we identified amplicon sequence variants identical to those in the starter, matching the bacteria Lactococcus lactis, Streptococcus thermophilus, Leuconostoc and the yeast Debaromyces. In raw milk kefir, additional sequence variants of Lactococcus lactis and the yeasts Pichia and Galactomyces could be identified, which were absent in heated milk kefir. Analysis of peptide compositions in kefirs indicated that the number and intensity of peptides drastically increased after fermentation. Heating of milk negatively affected the diversity of the peptide composition in kefir. Only raw milk kefir suppressed the acute allergic skin response to the food allergen ovalbumin in sensitised mice. These effects coincided with differences in the T-cell compartment, with lower percentages of activated Th1 cells and IFNg production after treatment with kefir made from heated milk. The results of this study indicate specific properties of raw milk kefir that may contribute to its additional health benefits.Competing Interest StatementTB is partly sponsored for his research activity by the Raw Milk Company. J.G. and B.v.E. are partly employed at Danone Nutricia Research. All other authors report no conflict of interest.ASVAmplicon Sequence VariantcatConcatenatedCFUColony Forming UnitCtCycle thresholdSCDefined Starter Culture eXact® 2 kefir, HansenEVExtracellular VesiclesITSInternal Transcribed SpacerNCBINational Centre for Biotechnology InformationPBSPhosphate Buffered Saline solutionHMHeated Milk (shortly boiled)HMKHeated Milk Kefir based on SCqPCRQuantitative real-time polymerase chain reactionRARelative AbundanceRMRaw MilkRMKRaw Milk Kefir based on SC