Utjecaj ne-toplinske obrade ultrazvukom visoke snage na stvaranje biofilma

undergraduate thesis

• Title (english): The influence of non-thermal treatment of high intensity ultrasound on formation biofilm
• Author: Andrea Ljubić
• Mentor: Anet Režek Jambrak (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Food Processes Engineering); Zagreb
• Defense date and country: 2017-06-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog rada je utvrditi utjecaj ne-toplinske obrade ultrazvukom visoke snage na stvaranje biofilma bakterijske kulture Listeria innocua ATCC 33090. Uzorci su ultrazvučno tretirani sondom frekvencije 20 kHz uz tri nezavisne varijable, amplituda (75%, 100%), vrijeme tretmana (5min, 10 min) i temperatura (40°C, 60°C). Rezultati su analizirani površinskom metodom (RSM) koristeći program STATGRAPHICS Centurion. Najviša redukcija stvaranja biofilma postignuta je nakon 5 min tretmana ultrazvukom pri temperaturi 60°C i 100 % amplitudi. Vrijednost biofilma se smanjila u odnosu na početnu vrijednost za 92.25 %. Kod 75 % amplitude i 60 °C te 5 min tretmana nije došlo do očekivane redukcije biofilma već do povećanja za 99.83 %. Temperaturni tretman (60 ⁰C) rezultirao je potpunom redukcijom 7.08 log10 CFU/mL što je ujedno i najviša inaktivacija bakterijskih stanica L. innocua. Prilikom ultrazvučnog tretmana na stvaranje biofilma i inaktivaciju utjecala je temperatura, razina ultrazvučne amplitude, vrijeme tretmana. Posljedično se formiraju različiti oblici radikala koji su mjera za intenzitet kavitacije. Radikali oštećuju stanicu i time je inaktiviraju.

Abstract (english)

The aim of this final work is to determine the influnece of non-thermal treatment of high intensity ultrasound on the formation of biofilm of Listeria innocua ATCC 33090. Samples were treated with the ultrasound probe with a frequency of 20 kHz with three independent variables, amplitude (75 %, 100 %), duration of treatment (5min, 10 min) and temperature (40 °C, 60 °C). The results were analyzed by surface method (RSM) using the STATGRAPHICS Centurion program. The highest biofilm reduction was achieved after the 5 minutes of ultrasound treatment at 60 ° C and 100 % of amplitude. The biofilm amount decreased in relation to the initial amount for 92.25 %. At the 75 % amplitude, 60 ° C and 5 minutes of treatment there was no expected reduction of biofilm. Biofilm formation was higher for 99.83 % comparing to the initial level. Temperature treatment (60 ⁰C) resulted in a total reduction of 7.08 log10 CFU / mL, which is the highest inactivation of L. innocua bacterial cells. During ultrasonic treatment formating biofilm and inactivation was influenced by temperature, ultrasonic amplitude level and treatment time. Consequently, different forms of radicals are formed which are the measure of the intensity of cavitation. They damage the cell and thereby inactivate them.

• Keywords: biofilm; kavitacija; Listeria innocua; stupanj redukcije; ultrazvuk
• Keywords (english): biofilm; cavitation; degree od reduction; Listeria innocua; ultrasound
• Language: croatian
• URN:NBN: urn:nbn:hr:159:341105
• Study programme: Title: Food Technology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-06-13 11:46:52