20.500.12556/DKUM-79852 Izolacija kefirana iz kefirja diplomsko delo univerzitetnega študijskega programa I. stopnje Kefiran isolation from kefir V diplomskem delu opisujemo potek fermentacije kefirnih zrn v mleku in nadaljnji postopek izolacije eksopolisaharida kefirana ter določitev vsebnosti sladkorjev. Najprej smo poskušali kefiran izolirati iz kefirnih zrn, vendar je bila zmes preveč gosta in zato izolacija ni bila možna. Izolacijo smo nato izvedli iz mlečnega kefirja. V sklopu eksperimentalnega dela smo spreminjali temperaturo fermentacije in vrsto mleka. Ugotavljali smo vpliv spremembe temperature na količino glukoze in galaktoze v kefiranu. Za določitev sladkorjev smo uporabljali sistem za tekočinsko kromatografijo visoke ločljivosti sklopljen z detektorjem za merjenje lomnega količnika (HPLC-RI). Fermentacija mlečnega kefirja je potekala v 1 L stekleni posodi, ki smo jo za en dan postavili v termostat. Po enem dnevu smo po določenem postopku izolirali kefiran in s pomočjo HPLC določili vsebnost sladkorjev. Ugotovili smo, da po izolaciji v vseh vzorcih dobimo višjo masno koncentracijo glukoze kot galaktoze, kar potrjuje prisotnost kefirana. Z dobljenimi rezultati smo potrdili, da je pri višji temperaturi višja masna koncentracija tako glukoze kot tudi galaktoze. Za primerjavo s polnomastnim mlekom smo izvedli fermentacijo tudi z mlekom, ki vsebuje manj mlečnih maščob (1,5 %). In the diploma work we describe the course of fermentation of kefir grains in milk and the further procedure of isolation of exopolysaccharide kefiran and determination of sugar content. We first tried to isolate kefiran from kefir grains, but the mixture was too thick and therefore isolation was not possible. The isolation was then made from milk kefir. As part of the experimental work, we changed the fermentation temperature and the type of milk. The effect of temperature change on the amount of glucose and galactose in kefiran was determined. A high-performance liquid chromatography system coupled to a refractive index detector (HPLC-RI) was used to determine the sugars. The fermentation of milk kefir took place in a 1 L glass container, which was placed in a thermostat for one day. After one day, kefir was isolated after a certain procedure and the sugar content was determined by HPLC. We found that after isolation in all samples we obtain a higher mass concentration of glucose than galactose. The obtained results confirmed that a higher mass concentration of both glucose and galactose was obtained at a higher temperature. For comparison with whole milk, fermentation was also performed with milk containing less milk fat (1,5%). kefir mleko fermentacija odvisnost od temperature HPLC kefir milk fermentation temperature dependence HPLC true true false [Z. Mesec] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2021-08-19 16:50:49 2021-09-22 06:05:11 2022-08-09 22:08:42 0000-00-00 00:00:00 2021 0 Maribor 0 Maribor VIII, 27 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 637.136.5:637.146.21(043.2) 77663235 UN_Mesec_Zala_2021.pdf UN_Mesec_Zala_2021.pdf 1 94321CC8C683DE6FC359F90B716F021F a191059229d63ccf4f92957285399975f3aa5ca263f4695d3a73a2e8dadc6a77 7e00fd5f-05aa-11ec-b44e-00155d581298 20.500.12556/dkum/ba5e1ffd-110c-4146-9f76-ae9f2e0c280f https://dk.um.si/Dokument.php?lang=slv&id=152322 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0