Kefiran is the clear or pale yellow polysaccharide gel exuded by dairy kefir or water kefir grains.
Dairy kefir grains are symbiotic consortia of bacteria and yeasts which ferment milk containing the complex sugar lactose, whereas water kefir grains contain less microbial diversity and can be cultured in water and sugar alone. Kefiran has been shown to exhibit certain medicinal qualities, and it contributes to the organoleptic (mouthfeel) qualities of kefir. Bacteria that produce kefiran have been identified as Lactobacillus kefiranofaciens and Lactobacillus delbrueckii subsp. bulgaricus.
- Maeda H, Zhu X, Omura K, Suzuki S, Kitamura S (2004). "Effects of an exopolysaccharide (kefiran) on lipids, blood pressure, blood glucose, and constipation". BioFactors 22 (1–4): 197–200. doi:10.1002/biof.5520220141. PMID 15630283.
- Maeda H, Zhu X, Suzuki S, Suzuki K, Kitamura S (August 2004). "Structural characterization and biological activities of an exopolysaccharide kefiran produced by Lactobacillus kefiranofaciens WT-2B(T)". J. Agric. Food Chem. 52 (17): 5533–8. doi:10.1021/jf049617g. PMID 15315396.
- Frengova GI, Simova ED, Beshkova DM, Simov ZI (2002). "Exopolysaccharides produced by lactic acid bacteria of kefir grains". Z. Naturforsch., C, J. Biosci. 57 (9–10): 805–10. PMID 12440716.