
Kefir contains lactic acid bacteria and yeasts. These microorganisms are confined in kefiran, a branched glucogalactan with antimicrobial, anti-tumor and anti-fungal properties .The purpose of this study was to analyze the structure of the polysaccharide in raw kefiran. Kefiran was produced from raw milk with. 5.0% fat and 10 grams of kefir grain. The polysaccharides were extracted by ethanol and then protein was separated by ammonium sulfate. Four different bands in the purified protein were revealed by gel electrophoresis. Separated proteins were heat resistant with anti-microbial properties. Structural analysis by means of FTIR, AFM and X-RD showed that by removing the antimicrobial protein, the remained polysaccharide formed zigzag-shaped micro-crystals of horseshoe with antibacterial characteristics. Enhancement of the resistance of bacteria to antibiotics, make this antibacterial polysaccharide useful in the production of polymer and drug delivery. To the best of our knowledge, the horse’s micro-crystal fiber of deproteinized kefiran with antibacterial activities is reported for the first time.