Proizvodnja egzopolisaharida s bakterijom Leuconostoc mesenteroides L3

master's thesis

• Title (english): Exopolysaccharides production by bacterium Leuconostoc mesenteroides L3
• Author: Ozren Hrsto
• Mentor: Jasna Mrvčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Fermentation and Yeast Technology); Zagreb
• Defense date and country: 2010-06-11, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U proizvodnji kiselog tijesta, kao starter kulture, glavnu ulogu imaju bakterije mliječne kiseline (BMK). U posljednje vrijeme, posebno se istražuju BMK koje proizvode egzopolisaharide (EPS) u cilju njihove primjene kao zamjene za hidrokoloide, koji se koriste u pekarstvu i imaju pozitivno djelovanje na volumen, teksturu, svježinu i rok trajanja kruha. Stoga je cilj ovog rada bio optimirati proces proizvodnje EPS u MRS podlozi i in situ s pomoću bakterije Leuconostoc mesenteroides. HPLC analiza kiselinskog hidrolizata EPS sintetiziranih u MRS podlozi pokazala je da je sintetizirani EPS homopolisaharid dekstran, dok su u hidrolizatu EPS sintetiziranih u tijestu detektirani glukoza te ksiloza i arabinoza koje potječu od polisaharida prirodno prisutnih u brašnu. Rezultati su također pokazali da je sinteza EPS i u MRS podlozi i u tijestu vezana za rast, a optimalni parametri procesa sinteze EPS su: statički uvjeti, vrijeme procesa 18h, temperatura 20oC te koncentracija saharoze 10%. Pri ovim uvjetima sintetizirano je oko 15 g/L EPS u MRS podlozi te oko 19 gEPS/kg brašna tijekom kiseljenja tijesta. Dodatak saharoze u cilju sinteze EPS tijekom kiseljenja tijesta nema značajan utjecaj na proizvodnju kiselina.

Abstract (english)

In the production of sourdough as a starter culture, lactic acid bacteria (LAB) have the main role. In recent years, LAB that produce exopolysaccharides (EPS) are especially researched for the purpose of their use as replacements for hydrocolloids, which are used in baking and have a positive effect on volume, texture, freshness and shelf life of bread. The aim of this study was to optimize the production process EPS in MRS medium and in situ using bacteria Leuconostoc mesenteroides. HPLC analysis of acidically hydrolyzed EPS synthesized in MRS medium showed that the synthesized EPS is homopolisaharid dextran, while in the hydrolyzed of EPS synthesized in dough detected glucose, xylose and arabinose. These sugars originated from polysaccharides naturally present in flour. The results also showed that the synthesis of EPS in MRS medium and dough are related to growth, and that optimal parameters of EPS synthesis are static conditions, during the process time of 18h, the temperature of 20ºC and sucrose concentration of 10%. Synthesized under these conditions was synthesized about 15 g / L EPS in MRS medium, and about 19 g EPS / kg of flour dough during souring. Addition of sucrose in order to synthesize EPS during the dough souring has no significant effect on acid production.

• Keywords: egzopolisaharidi; Leuconostoc mesenteroides L3; kiselo tijesto
• Keywords (english): exopolysaccharides; Leuconostoc mesenteroides L3; sourdough
• Language: croatian
• URN:NBN: urn:nbn:hr:159:641212
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-08-25 07:29:16