doctoral thesis
The impact of genotype and environmental conditions on malt quality parameters of winter barley (Hordeum vulgare L.)

Gordana Šimić (2009)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Food Technologies
Metadata
TitleUtjecaj genotipa i okolišnih uvjeta na parametre sladarske kakvoće ozimog ječma (Hordeum vulgare L.)
AuthorGordana Šimić
Mentor(s)Žaneta Ugarčić
Abstract
Ječam namijenjen za slađenje mora udovoljiti posebnim zahtjevima koje postavlja industrija piva. Sladarsku kakvoću uvjetuje genotip, iako značajan utjecaj imaju i okolišni uvjeti kao što su tip tla te fluktuacije u temperaturi i padalinama tijekom uzgoja. Cilj je ovog istraživanja bio na temelju odabranih ozimih kultivara ječma uzgojenih na različitim agroekološkim područjima ispitati utjecaj genotipa i okolišnih uvjeta na sladarsku kakvoću. U istraživanju su korištena tri kultivara ozimog ječma, a pokus je postavljen na četiri lokacije (tla različite plodnosti) tijekom tri vegetacijske godine. U radu je određena kakvoća zrna ječma koji je mikroslađenjem preveden u slad. Laboratorijskim ispitivanjima određena je kakvoća slada koja je obuhvatila parametre koji opisuju citolitičku, amilolitičku i proteolitičku razgrađenost slada. Primjenom visokotlačne tekućinske kromatografije obrnutih faza (RP-HPLC) određena je hordeinska frakcija skladišnih bjelančevina u zrnu ječma i u dobivenom sladu u svrhu određivanja njihove razgrađenosti tijekom slađenja. Na temelju dobivenih rezultata za količinu ekstrakta, značajnog parametra u ocjeni slada, između ispitivanih kultivara nije utvrđena statistički opravdana razlika, ali je postojala značajna razlika između ispitivanih godina i lokacija. Statistička značajnost razlika u prosječnim vrijednostima količine bjelančevina u zrnu ječma ukazuje na klimatsku varijabilnost istraživanih vegetacijskih razdoblja te na veliki utjecaj genotipa i okolišnih uvjeta na formiranje udjela bjelančevina u zrnu. Količina β-glukana u sladu ukazuje na značajnost razlika između kultivara, kao i na utjecaj godine i lokacije na ispitivano svojstvo. Prema prosječnim vrijednostima, kultivar Vanessa pokazao je značajnije veću aktivnost u pogledu citolitičke, amilolitičke i proteolitičke razgrađenosti u odnosu na kultivare Zlatko i Barun, iako je u prosjeku imao veći udio bjelančevina u zrnu. Korelacijska analiza pokazala je da je većina parametara sladarske kakvoće visoko međusobno povezana bilo u pozitivnom i ili u negativnom smjeru. Ekstrakt slada značajno negativno korelira s količinom hordeina u zrnu ječma i količinom β-glukana. Promatrajući utjecaj pojedinih hordeinskih skupina, uočljiv je izrazito jak negativan utjecaj B skupine hordeina na ekstrakt slada. Procjena stupnja razgrađenosti hordeina tijekom slađenja u velikoj mjeri odražava promjene koje se događaju s bjelančevinama zrna ječma tijekom slađenja te jasno pokazuje razlike između kultivara vezano uz razgrađenost bjelančevina. Provedbom pokusa i proučavanjem značajnosti utjecaja okolišnih uvjeta na kakvoću zrna i slada dobiveni su vrijedni podaci o učinku genotipa u datim okolnostima koji će se moći koristiti pri procjeni stabilnosti parametara sladarske kakvoće u selekciji genotipova pogodnih za naše uzgojno područje.
Keywordsbarley malting quality genotype
Parallel title (English)The impact of genotype and environmental conditions on malt quality parameters of winter barley (Hordeum vulgare L.)
Committee MembersAlojzije Lalić (committee chairperson)
Žaneta Ugarčić (committee member)
Daniela Horvat (committee member)
Drago Šubarić (committee member)
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsDepartment of Food Technologies
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
Engineering
UDK631/632
APPLIED SCIENCES. MEDICINE. TECHNOLOGY
Agriculture. Plant diseases. Plant protection
Study programme typeuniversity
Study levelpostgraduate
Study programmeFood Engineering
Academic title abbreviationdr. sc.
Genredoctoral thesis
Language Croatian
Defense date2009-02-11
Parallel abstract (English)
Barley aimed for malt production must meet a special requirements proposed by brewing industry. Malting quality is controlled by genotype, although environmental conditions like temperature and precipitation fluctuations have also significant influence on malt quality. The aim of this study was to explore the impact of genotype and environmental conditions, based on selection of winter cultivars grown at different agroecological environments, on malting quality. This study included three winter type barley cultivars and field trials were conducted at four different locations (different soil fertility) during three vegetation years. Prior to micromalting barley grain quality was determined. Quality of malt was determined by laboratory analysis of parameters of cytolytic, amilolytic and proteolytic degradation of malt. Reversed-phase high-performance liquid chromatography analysis was applied for determination of endosperm hordein fractions in barley grain and in malt, with aim to determine the hordein degradation during malting. Based on obtained results for malt extract content, which is important parameter in malt evaluation, there was no evidence that would point out the statistically significant difference between years and locations included in this study. Statistically significant difference among average values of barley grain protein content points to the climate variability of investigated vegetation periods and to the great impact of genotype and environmental conditions on a barley grain protein formation. The results of β-glucan content in malt showed significant difference between cultivars. Significant impact of year and location on this parameter was also noticed. According to average values, cultivar Vanessa showed significantly higher activity of enzymes in terms of cytolytic, amilolytic and proteolytic degradation of the endosperm when compared to cultivars Zlatko and Barun, in spite of higher average grain protein content. The results of the analysis of linear correlation carried out on the particular malt quality data obtained showed high coherence either in positive or negative direction. Malt extract content significantly negatively correlates with barley grain protein content and β-glucan content. Observing the impact of the individual hordein groups, the significantly negative impact of the B hordein on malt extract content was noticed. One of the important physical-chemical changes that occur during malting is degradation of the hordein proteins and conversion to soluble paptides and amino acids. Assessment of the rate of hordein degradation clearly indicates differences among cultivars in term of protein degradation. Implementation of the field trial and study on the impact of the environmental conditions on barley grain and malt quality gives valuable data on genotype effect in given circumstances that will be used for malt quality parameters stability estimation in selection of genotypes of favorable breeding value.
Parallel keywords (Croatian)ječam sladarska kakvoća genotip
Extent141 str.; ilustr., graf. prikazi; 30 cm
Versionaccepted version
Resource typetext
Access conditionOpen access
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
Noteaccepted version
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:155652
CommitterSanda Hasenay