20.500.12556/RUL-182144 Vpliv protokolov liofilizacije na preživetje probiotičnih bakterij v jogurtu The effect of freeze-drying protocols on survival of probiotic bacteria in yogurt Liofilizacija mlečnih izdelkov predstavlja izziv zaradi občutljivosti probiotičnih bakterij na procesne pogoje sušenja. V diplomski nalogi je bil preučen vpliv treh protokolov liofilizacije na preživetje probiotičnih bakterij v jogurtu. Jogurt je bil liofiliziran po agresivnem, srednje agresivnem in konzervativnem protokolu, ki so se razlikovali po temperaturi v primarni fazi sušenja. Pri agresivnem –25 °C, pri srednje agresivnem –15 °C in pri konzervativnem –5 °C. Potek procesa je bil spremljan z meritvijo gostote toplotnega toka. Živost bakterij v svežih in rehidriranih vzorcih je bila določena z metodo kolonijsko formirajočih enot (angl. colony-forming unit). Rezultati so pokazali, da srednje agresivni in konzervativni protokol omogočata primerljivo preživetje bakterij, pri čemer je srednje agresivni protokol za dve uri krajši. Freeze-drying of dairy products poses a challenge due to the susceptibility of probiotic bacteria to the process conditions of dehydration. The influence of three individual freeze-drying protocols on the survival of probiotic bacteria in yogurt has been studied for the purpose of this thesis. The protocols differ in temperature during primary drying and so yogurt samples have been dry-frozen under an aggressive protocol at –25 °C, under a medium-aggressive protocol at –15 °C, and under a conservative protocol at –5 °C. The course of the dry-freezing process has been monitored with the measuring of heat flux. The viability of bacteria in samples of fresh and dehydrated yogurt has been determined by the colony-forming unit method. Results have shown that the medium-aggressive protocol and the conservative protocol ensure comparable viability of bacteria, whereas the medium-aggressive protocol was two hours shorter in duration. liofilizacija probiotik jogurt gostota toplotnega toka procesni protokol freeze-drying probiotic yogurt heat flux process protocol true false false [L. Zorman] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2026-04-25 08:30:25 2026-04-25 08:30:46 2026-05-05 11:16:13 0000-00-00 00:00:00 2026 0 Ljubljana 0 XVIII, 45 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 57.086.13:613.292(043.2) 285550 277047299 46873.pdf 46873.pdf 1 DFC082BBA99185A82DDFB1935836C68F 4a7b52cb949939e1f6e491f18bc25cd072351b034aa90dac7e7e5b59f750b988 09a5fd25-4070-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=233118 Fakulteta za strojništvo 0 0 0