Proizvodnja kruha produžene trajnost s pomoću bakterije Leuconostoc mesenteroides

master's thesis

• Title (english): Production of bread with extended shelf life using the Leuconostoc mesenteroides bacteria
• Author: Goran Strganac
• Mentor: Jasna Mrvčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Fermentation and Yeast Technology); Zagreb
• Defense date and country: 2015-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U današnje vrijeme u pekarstvu se sve više koristi kiselo tijesto za povećanje tehnološke, organoleptičke, mikrobiološke, nutritivne i zdravstvene kvalitete pekarskih proizvoda. Ti pozitivni učinci rezultat su djelovanja mikroflore kiselog tijesta, bakterija mliječne kiseline (BMK) i kvasaca. U radu je ispitan utjecaj dodatka različite količine kvasca (0,5 %, 1 % i 1,8 %) i tekućeg kiselog tijesta (10 %, 15 % i 20 %) u kojem prevladava bakterija Leuconostoc mesenteroides na pokazatelje kvalitete polubijelog pšeničnog kruha (volumen, senzorska svojstva, tvrdoću, kinetiku starenja, profil teksture). S obzirom da je korišten soj heterofermentativnih BMK Leuconostoc mesenteroida koji proizvode mliječnu i octenu kiselinu kao primarne metabolite, koncentracija tih metabolita određena je pomoću HPLC-a, dok je tvrdoća sredine i profil teksture kruha određen s pomoću analizatora teksture. Dodatkom kiselog tijesta povećan je volumen kruha, poboljšana su senzorska svojstva, usporeno je starenje i poboljšana je tekstura kruha u odnosu na standardni kruh. Rezultati pokazuju da su optimalni parametri za proizvodnju kruha produžene trajnosti pomoću kiselog tijesta 1,8 % kvasca i 15 % kiselog tijesta jer je taj uzorak ocjenjen najkvalitetnijim nakon senzorskog ocjenjivanja. Na temelju dobivenih rezultata može se zaključiti da je bakterija Leuconostoc mesenteroides pogodna za industrijsku proizvodnju kruha produžene trajnosti.

Abstract (english)

At the present time sourdough is increasingly used in bread making in order to increase the technological, organoleptic, microbiological, nutritive, and health quality of bakery products. These positive effects result from the action of the microflora of the sourdough, lactic acid bacteria (LAB) and yeast. The thesis examines the effect of adding different amounts of yeast (0.5%, 1% and 1.8%) and liquid sourdough (10%, 15% and 20%) in the final doughing on semiwhite wheat bread quality indicators (volume, sensory properties, hardness, aging kinetics, texture profile). Given that the strain of heterofermentative LAB Leuconostoc mesenteroides which produce lactic and acetic acid as primary metabolism products was used, the concentration of these metabolites was determined using HPLC. The hardness of the middle part of the bread and the texture profile of the bread were determined using a texture analyser. With the addition of sourdough the volume increases, sensory properties improve, aging slows down and the texture of bread improves in comparison to standard bread. The results show that the optimal parameters for bread production using sourdough are 1.8% of yeast and 15% of sourdough since this sample had the highest quality number after sensory evaluation. Based on the obtained results, we can conclude that Leuconostoc mesenteroides is suitable for industrial production of bread with extended shelf life.

• Keywords: Leuconostoc mesenteroides; kiselo tijesto; kvasac; kvaliteta kruha
• Keywords (english): Leuconostoc mesenteroides; sourdough; yeast; quality bread
• Language: croatian
• URN:NBN: urn:nbn:hr:159:403826
• 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 12:57:46