Utjecaj uvjeta smrzavanja na svojstva kiselog tijesta

master's thesis

• Title (english): Influence of freezing conditions on sourdough properties
• Author: Nikola Maričić
• Mentor: Dubravka Novotni (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Cereal Chemistry and Technology); Zagreb
• Defense date and country: 2015-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog rada bio je odrediti utjecaj načina smrzavanja i vremena smrznutog skladištenja na svojstva ječmenog kiselog tijesta. U radu su pripremljena četiri ječmena kisela tijesta pomoću startera W. cibaria ili L. reuteri, sa šećerom ili bez, a smrznuta su imerzijom i strujom hladnog zraka u šokeru i skladištena kroz četiri tjedna. U kiselom tijestu, broj živih stanica je smanjen postupkom smrzavanja te skladištenjem. Ukupna kiselost i pH vrijednosti bile su tipične za kisela tijesta i nisu se značano razlikovale ovisno o starteru, dodatku šećera, metodi smrzavanja i skladištenju. Sposobnost dizanja krušnog tijesta koje se sastojalo od polubijelog pšeničnog brašna i ječmenog kiselog tijesta (20 % tijesta) ispitana je u reofermentometru. Dodatak ječmenog kiselog tijesta pripremljenog bilo s W. cibaria ili L. reuteri u količini od 20% utjecao je na poboljšana svojstva dizanja krušnog tijesta u odnosu na dodatak nefermentiranog ječmenog brašna. Ovi rezultati ukazuju na mogućnost uporabe smrznutog kiselog tijesta u industrijskoj proizvodnji miješanog ječmenog kruha za potrošače koji žele funkcionalni pekarski proizvod, jer je integralni ječam izvor β-glukana.

Abstract (english)

The goal of this study was to determine the impact of freezing conditions and frozen storage time on barley sourdough properties. In this study, four barley sourdougs were made using W. cibaria or L. reuteri, with or without adding sugar, frozen by imersion or in blast freezer and storaged for four weeks. In sourdough, bacteria cell counts were reduced by both freezing and during frozen storage. Total titrable acidity and pH values were typical for sourdough and were not significantly differed depending on starter, sugar add, freezing conditions and storage. Leavening ability of composite dough containing wheat flour and barley sourdough (20 % at dough basis) was determined in rheofermentometer. Addition of 20 % barley sourdough either with W. cibaria or L. reuteri had positive effect on bread dough leavening ability compared to addition of unfermented barley flour. These results show the possibility of using frozen sourdough in industrial production of composite barley bread for consumers that want functional bakery product's, because whole grain barley is the source of β-glucan.

• Keywords: ječmeno kiselo tijesto; smrzavanje; Lactobacillus reuteri; Weissella cibaria; reofermentometar
• Keywords (english): barley sourdough; freezing; Lactobacillus reuteri; Weissella cibaria; rheofermentometer
• Language: croatian
• URN:NBN: urn:nbn:hr:159:291962
• 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: 2017-05-03 09:52:40