Utjecaj probiotičkog soja Lactobacillus paracasei L26 i transglutaminaze na svojstva čvrstog jogurta

master's thesis

• Title (english): Influence of the probiotic strain Lactobacillus paracasei L26 and transglutaminase on the properties of set-style yoghurt
• Author: Inja Dražić
• Mentor: Jagoda Šušković (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: 2008-01-31, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom je radu ispitan utjecaj transglutaminaze i probiotičke kulture Lactobacillus paracasei L26 na kvalitetu i senzorska svojstva čvrstog jogurta. Za proizvodnju jogurta je korišteno svježe homogenizirano mlijeko s 3,2 % mliječne masti kojem je dodana probiotička kultura Lactobacillus paracasei L26, te enzim transglutaminaza aktivirana 1,5 h pri 55 °C. Enzim je zatim inaktiviran postupkom pasterizacije (15 min pri 85 °C). Nakon hlađenja na 43 °C, mlijeko za proizvodnju čvrstog jogurta je inokulirano smrznutom starter kulturom (BT10X i 100F) i probiotičkom kulturom Lactobacillus paracasei L26. Također su proizvedeni i kontrolni uzorci jogurta bez dodatka transglutaminaze i probiotičke kulture. U radu je određivan fizikalno-kemijski sastav mlijeka i jogurta, broj živih stanica probiotičke kulture Lactobacillus paracasei L26 kao i senzorska svojstva proizvedenog čvrstog jogurta. Utvrđeno je da su proizvedeni čvrsti jogurti s probiotičkom kulturom Lactobacillus paracasei L26 i transglutaminazom čvršći, da pokazuju manju sinerezu te su dobili višu ocjenu senzorskih svojstava u odnosu na kontrolne uzorke jogurta. Broj živih stanica Lactobacillus paracasei L26 je ostao visok tijekom svih 28 dana čuvanja jogurta. Fermentacija jogurta s dodatkom transglutaminaze traje kraće nego fermentacija jogurta bez dodatka transglutaminaze.

Abstract (english)

Research was undertaken to investigate the influence of transglutaminase and probiotic culture Lactobacillus paracasei L26 on the quality and sensoric properties of set-style yoghurt. Fresh homogenised milk with 3,2 % of milk fat has been used for the yoghurt production, with addition of Lactobacillus paracasei L26 and transglutaminase activated during 1,5 h at 55 °C. Enzyme inactivation was completed by pasterization of milk during 15 minutes at 85 °C. Milk was inoculated with the yoghurt starter culture (BT10X and 100F) and probiotic culture Lactobacillus paracasei L26 afer cooling to the temperature of 43 °C. Control samples were also made, without addition of transglutaminase and probiotic culture. Physico-chemical parameters of milk and set-style yoghurt, as well as viable count of probiotic culture Lactobacillus paracasei L26, and sensoric properties of produced set-style yoghurt have been determined. It has been shown that produced set-style yoghurts with probiotic culture Lactobacillus paracasei L26 and transglutaminase had higher firmness, less syneresis, and better sensoric properties than control yoghurts. The viable count of Lactobacillus paracasei L26 stayed high during all 28 days of storage. Fermentation of yoghurt samples containing transglutaminase lasted shorter than fermentation of samples without transglutaminase.

• Keywords: čvrsti jogurt; Lactobacillus paracasei; probiotik; senzorska svojstva; transglutaminaza
• Keywords (english): set-style yoghurt; Lactobacillus paracasei; probiotic; sensoric properties; transglutaminase
• Language: croatian
• URN:NBN: urn:nbn:hr:159:030132
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-04 13:54:33