Determination of physical properties of kefiran produced by kefir grains using different carbon sources

Bacterial polysaccharide structure obtained from kefir grain is described as kefiran. Kefiran structure found in kefir grain is stated to have a lot of functional properties.In this thesis study, kefir grains were growned in different carbon sources. Extractions of bacterial polysaccharide in kefir grains was carried out. It was aimed that determining rheological properties, the change in their mass and the chemical structure of obtained kefiran with nuclear magnetic resonance. In the development process of kefir grains, milk was enriched with glucose, galactose and lactose as source of carbon. This enrichment was not implemented to the control group. Kefiran of all kefir grains were extracted.The significant increase in kefir grain biomass as determined in GAKG sample. The amount of kefiran obtained from GAKG sample is determined the highest 610,96 mg L-1 (Lactose equivalent). Viscosity rates in CKG, GAKG, LKG and GLK samples are determined respectively as 17,9; 18,5; 14,6 and 29,2 (66/1 shear rate). In order to determine the structures of lyophilised kefirans, samples were analysed by means of Nuclear Magnetic Resonance (NMR) technique. Measurements are carried out with trifloroasetik asit (TFA) solvent in 24-65 centigrade degrees and 13C and 1H spectrums are obtained. Kefiran structure from kefir grains developed in different carbon sources were not determined as significant. This study will contribute to the literature by determination of kefiran structure which is a natural biopolymer structure and use of it in the food sector especially in the area of fermented dairy products developing texturized properties as a stabilizer agent.