Bioraznolikost mikrobne populacije bakterija mliječne kiseline u autohtonim fermentiranim proizvodima

undergraduate thesis

• Title (english): Biodiversity microbe population lactic acid baceteria in autochtone fermented products
• Author: Sandra Pogačić
• Mentor: Jasna Novak (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Antibiotic, Enzyme, Probiotic and Starter Cultures Technology); Zagreb
• Defense date and country: 2011-07-22, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom radu ispitana je bioraznolikost mikrobne populacije bakterija mliječne kiseline u tradicionalno proizvedenom kiselom kupusu. Provedena je izolacija autohtono prisutnih bakterija s ciljem definiranja probiotičkih starter kultura, a osobit je naglasak stavljen na tehnološke karateristike odabranih sojeva. Na temelju klasičnih mikrobioloških metoda i analizom ukupnih staničnih proteina pomoću SDS-PAGE elektroforeze, te fermentacijskih profila šećera, odabrani autohtoni bakterijski izolati identificirani su kao BMK. Sve odabrane autohtone BMK nakon prekonoćnog uzgoja u MRS hranjivoj podlozi uspješno spuštaju pH vrijednosti ispod 4,44. Većina izolata nije osjetljiva na ihnibicijsko djelovanje nisina u koncentraciji 75 μg/l. Visoke koncentracije NaCl (6.0%) najuspješnije toleriraju SF2, SF9 i SF13. Liofilizacijom su pripremljeni suhi aktivni preparati odabranih bakterijskih sojeva u različitim lioprotektorima, saharozi, te prebioticima inulinu i sorbitolu. Nakon liofilizacije broj živih stanica primjenjenih kultura je iznosio iznad 1017CFU/g, što je važno svojstvo s tehnološkog aspekta priprava, čuvanja i primjene sojeva u industrijskom mjerilu.

Abstract (english)

In this thesis the biodiversity of the lactic acid bacteria (LAB) population in the traditional produced sauerkraut was investigated. Autochthonous LAB were isolated with an aim to define probiotic starter cultures, with special emphasis on the technological characteristics of the chosen strains. Chosen bacterial autochthonous isolates are identified as LAB based on conventional microbiological methods, SDS-PAGE analysis of the whole cell protein profiles and fermentation of the sugar profiles. All autochthonous chosen LAB, after overnight cultivation in MRS broth, successfully lowered pH to 4.44. Most of the isolates were not inhibited by nisin in concentration of 75μg/l. SF2, SF9 and SF3 tolerate high concentration of NaCl (6,0%). Dry active products of the chosen strains were freeze-dried in different lyoprotectors, sucrose, inulin, sorbitol. After freezedrying, the cell counts were higher than 107CFU/g, what is an important characteristic from the technological aspect in order to , storage and applying strains in industrial measure.

• Keywords: bakterije mliječne kiseline; liofilizacija; probiotičke starter kulture; tolerancija na nisin; tolerancija na natrijev klorid
• Keywords (english): lactic acid bacteria; probiotics; starter cultures
• Language: croatian
• URN:NBN: urn:nbn:hr:159:724602
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-19 10:45:59