Sterilized reconstituted skim milk (10% w/v) and soymilk
were each inoculated with 5% kefir grains. All inoculated
milk and soymilk samples were incubated at 20 8C for 24 h.
During the fermentation, samples were taken every 8 h for
analysis of volatile-compound composition. At the end of
fermentation, kefir grains were filtered through cheesecloth
for visual inspection, electron microscope study and extraction
of polysaccharides.