Brojnost probiotskih bakterija u domaćim fermentiranim namirnicama

master's thesis

• Title (english): Quantity of probiotic bacteria in home-made fermented food
• Author: Ana Grizelj
• Mentor: Tomislav Ivanković (mentor)
• Committee member: Tomislav Ivanković (predsjednik povjerenstva)
• Committee member: Mirela Sertić Perić (član povjerenstva)
• Committee member: Nenad Judaš (član povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2022-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Probiotici su živi mikroorganizmi, najčešće bakterije mliječne kiseline, koji imaju
blagotvorno djelovanje na zdravlje domaćina. Cilj rada je identificirati probiotičke
bakterije u domaćem rasolu te usporediti brojnost probiotičkih bakterija između
komercijalno dostupnih probiotika, domaćeg rasola te kupovnih i domaćih mliječnih
proizvoda. U radu je korišteno 9 različitih uzoraka domaćeg rasola, 4 različita kupovna
probiotika, 4 kupovna mliječna proizvoda te 4 domaća. Pripremljena su decimalna
razrijeđenja svih uzoraka te su nacijepljena na MRS hranjivu podlogu. Izolirane
probiotičke bakterije domaćeg rasola fenotipski su karakterizirane metodom bojanja po
Gramu te su identificirane tehnologijom MALDI-TOF, a utvrđeno je da su prisutne
bakterijske vrste Levilactobacillus brevis i Levilactobacillus buchneri (gram-pozitivne
bakterije štapićastog oblika) te Pediococcus parvulus (gram-pozitivna bakterija
okruglog oblika). Ovim je radom utvrđeno da broj bakterija u uzorcima domaćeg rasola
iznosi 8,17±5,03 × 107 CFU mL-1, uzorci kupovnih mliječnih proizvoda sadrže
4,11±1,62 × 107 CFU mL- , domaći mliječni proizvodi sadrže 3,20±1,91 × 107 CFU
mL-1, a komercijalno dostupni probiotici sadrže 4,88±0,54 × 1010 CFU g
-1. Predlaže se daljnje istraživanje s više uzoraka domaćih namirnica kako bi se detaljnije
usporedile prisutne bakterijske vrste te njihove brojnosti.

Abstract (english)

Probiotics are living microorganisms. They are most often lactic acid bacteria which
have a beneficial effect on the host's health. This work aims to identify probiotic
bacteria in homemade cabbage brine and compare the number of probiotic bacteria
between commercially available probiotics, homemade brine, and store-bought and
domestic dairy products. Various samples were used in the study: 9 of homemade
cabbage brine, 4 of commercially available probiotics, 4 of store-bought dairy
products, and 4 of homemade dairy products. Decimal dilutions of all samples were
prepared and inoculated onto MRS nutrient medium. The isolated probiotic bacteria of
homemade cabbage brine were phenotypically characterized by the Gram staining
method. The bacteria were then identified by MALDI-TOF technology. Bacterial
species observed are Levilactobacillus brevis and Levilactobacillus buchneri (grampositive rod-shaped bacteria) and Pediococcus parvulus (round-shaped gram-positive bacteria). This work determined that the number of bacteria in samples of homemade cabbage brine is 8.17±5.03×107 CFU mL-1 . Commercially available dairy products
contain 4.11±1.62×107 CFU mL-1, while domestic dairy products showed 3.20±1.91
×107 CFU mL-1. Commercially available probiotics have 4.88±0.54×1010 CFU g-1. It is
suggested further research with more samples of homemade foods for a more detailed
comparison of the bacterial species present and their quantity.

• Keywords: mliječni proizvodi; bakterije mliječne kiseline; rasol; jogurt; kiselo mlijeko; kefir
• Keywords (english): dairy products; lactic acid bacteria; cabbage brine; yogurt; sour milk; kefir
• Language: croatian
• URN:NBN: urn:nbn:hr:217:347231
• Study programme: Title: Integrated undergraduate and graduate university study of Biology and Chemistry Education; specializations in: Integrated undergraduate and graduate university study of Biology and Chemistry Education; Course: Integrated undergraduate and graduate university study of Biology and Chemistry Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije biologije i kemije (magistar/magistra edukacije biologije i kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2024-09-19
• Created on: 2022-10-10 11:40:21