Lizozim kao prirodni prehrambeni konzervans

master's thesis

• Title (english): Lysozyme as natural food preservative
• Author: Tanja Bertović
• Mentor: Suzana Rimac Brnčić (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: 2014-07-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Lizozim iz bjelanjka kokošjeg jajeta je enzim (EC 3.2.1.17) koji hidrolizira β(1,4) glikozidnu vezu između N-acetilmuraminske kiseline i N-acetilglukozamina u staničnoj stjenci bakterija. Pokazuje antimikrobnu aktivnost prema Gram-negativnim bakterijama, kao što je E.coli. Cilj ovog rada je ispitati utjecaj nativnog lizozima, lizozima osušenog zagrijavanjem, lizozima osušenog zagrijavanjem i obogaćenog izo-aspartilom, izo-aspartil lizozima, nativnog oblika lizozima i sukcinimid lizozima na obje, i vanjsku i unutarnju membranu, in vivo. Djelovanje nativnog i osušenog lizozima izaziva različite posljedice na membranu bakterije. Osušeni lizozim uzrokuje veće i/ili više pora na vanjskoj membrani i učinkovitije djeluje na membranski potencijal. Može se pretpostaviti da su ti snažniji utjecaji na membrane bakterije zbog izmjena u fizikalno-kemijskim karakteristikama lizozima osušenog zagrijavanjem u odnosu na nativni lizozim. Međutim, lizozim osušen zagrijavanjem je smjesa tri izoforme: izo-aspartil lizozima, nativnog oblika lizozima i sukcinimid lizozima. Svaka izoforma uzrokuje specifičan poremećaj strukture ili vanjske ili unutarnje membrane.

Abstract (english)

Hen egg white lysozyme is an enzyme (EC 3.2.1.17) which catalysing hydrolysis of the bacterial cell walls by cleaving the β-1,4-glycosidic bonds between N-acetylmuraminic acid and N-acetylglucosamine residues. It has been demonstrated to have antimicrobial activity against Gram-negative bacteria such as E. coli. In this study, the effect of native lysozyme, dry-heated lysozyme, dry-heated enriched with iso-aspartyle, iso-aspartyle lysozyme, native-like lysozyme and succinimide lysozyme on both the outer and inner membranes have been investigated, in vivo. Activities of native and dry-heated lysozyme induce different consequences on the bacterial membranes. Dry-heated lysozyme induces larger and/or more pores in the outer membrane and it disrupt the membrane potential more efficiently. It can be assumed that these stronger effects on the bacterial membranes are due to the modifications in the physico-chemical characteristics of dry-heated lysozyme compared to native lysozyme. However, dry-heated lysozyme is a mixture of three different isoforms: iso-aspartyle lysozyme, native-like lysozyme and succinimide lysozyme. Each of the dry-heated lysozyme isoforms affords a specific disturbance of either the outer or the inner membrane.

• Keywords: lizozim; izoforme lizozima; antimikrobna aktivnost; Gram-negativna bakterija
• Keywords (english): lysozyme; isoforms of lysozyme; antimicrobial activity; Gram-negative bacteria
• Language: croatian
• URN:NBN: urn:nbn:hr:159:366773
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-04-28 11:49:10