Trans-2-nonenal is an aldehyde contributing to an unpleasant off-flavor and odor of rancid butter in stored beer. The automated solid-phase microextraction technique (SPME) coupled with gas chromatography (GC) and solidphase dynamic extraction (SPDE) coupled with gas chromatography were optimized and introduced to determine trans-2-nonenal in barley, malt and beer. Five types of SPME fibers coated with different stationary phases (100 lm PDMS, 65 lm PDMS/DVB, 85 lm CAR/PDMS, 50/30 lm DVB/CAR/PDMS, 85 lm PA) and two needles (PDMS, PDMS/AC) were compared and tested for their efficiencies in the headspace (HS) SPME and SPDE determination of trans-2-nonenal in barley, malt and beer. The highest extraction efficiency of HS-SPME was achieved with the PDMS/DVB fiber, and addition of 1.5 g of NaCl, extraction time was 20 min at 60°C. The highest extraction efficiency of HS-SPDE was obtained with the PDMS needle, 15 extraction strokes at 60°C and addition of 1.5 g of NaCl. Trans-2-nonenal was identified with the method of HS-SPME coupled gas chromatography-mass spectrometry (GC-MS); the samples were analyzed using the HS-SPME-GC-coupled gas chromatography-flame ionization detector (GC-FID) technique.
485Fusarium head blight (FHB) is a worldwide distributed cereal disease that is caused by fungi of the Fusarium genus. Infection of plants can result in yield reduction and accumulation of toxic secondary fungal metabolites, mycotoxins in kernels (Windels 2000, Takeda 2004). The number of papers dealing with FHB on barley is generally much lower than that of research studies on wheat. It is due to a much greater economic importance of wheat as a cereal crop, but as well as to the fact that FHB causes larger economic losses in wheat than in barley. Though the two crops are attacked by identical FHB pathogens, there are differences in their infection responses. In general, barley is less susceptible to FHB than wheat. Grain yield is affected by FHB more in wheat than in barley, however a higher mycotoxin concentration is observed in the latter due to outer cover layers (lemma and palea) that are parts of the kernel from harvest to end use (Steffenson 2003). Produced toxins are harmful to human health and can induce serious diseases. The mycotoxins are deactivated neither in malting nor in brewing processes. Moreover, they can influence beer flavour and cause gushEvaluation of spring barley genotypes with different susceptibility to Fusarium head blight using molecular markers ABSTRACTOne of cereal diseases that has gained a greater importance for growers, processing industry as well as for breeders in many regions of the world is Fusarium head blight (FHB) caused by fungi of the Fusarium genus. The objectives of this study were to test diversity among spring barley breeding lines exhibiting various sensitivity to FHB and to find RAPD markers and AFLP markers that will distinguish between susceptible and resistant and/or moderately resistant genotypes. A test of a set of spring barley genotypes artificially infected by fusaria in field trials was carried out. Based on the results from field and laboratory evaluation and deoxynivalenol (DON) content assessment, barley genotypes with different responses to FHB were selected. The genotypes were hybridized and doubled haploid (DH) lines were derived in F 1 generation using the in vitro androgenesis method. Initial parental components and derived DH lines were tested for FHB infection and DON content. A set of parental genotypes of spring barley was tested with 80 RAPD markers. A RAPD marker (H30) was detected which enabled to distinguish between very susceptible parental genotypes and other resistant or moderately resistant spring barley genotypes based on the fragment of about 1300 bp. This specific product was screened in 23 DH lines derived from crosses of parental genotypes of spring barley and detected in 10 DH lines. During the study, some DH lines were selected that exhibited improved resistance to Fusarium infection. A low infection level and low DON content was found in the line DH 4/2 derived from CI 4196 × Foster. The AFLP technique was used to analyse parental genotypes of spring barley. The detected markers can be further evaluated and employed to select ...
1Výzkumný ústav pivovarský a sladařský, a. s., Sladařský ústav Brno, Mostecká 7, 614 00 Brno Research Institute of Brewing and Malting, Plc., Malting Institute, Mostecká 7, 614 ÚVODHlavní surovinou pro výrobu sladu a následně piva na území České republiky od konce 19. století je jarní ječmen. Postupně se zvyšují a konkretizují požadavky na kvalitu sladovnického ječmene.Stále ne zcela probádanou a doceněnou oblastí zůstává u obilek ječmene jejich enzymatická činnost. Enzym lipoxygenasa katalyzuje oxidaci nenasycených mastných kyselin s více dvojnými vazbami, obsahujícími cis-1,4-pentadienovou skupinu, molekulovým kyslíkem. Řetězovou reakcí vznikají přechodně peroxidy nenasycených mastných kyselin, které se štěpí na karbonylové sloučeniny (aldehydy, ketony) nebo mastné kyseliny s krátkými řetězci. Vytvářejí se tím sloučeniny s charakteristickými vůněmi a chutěmi. Mezi substráty enzymu lipoxygenasy patří nutričně významné esenciální mastné kyseliny linolová, linolenová a arachidonová. Mohou být oxidovány i acylglyceroly a další estery zmíněných mastných kyselin.Základní složkou podílející se na žluklé chuti v uskladněném pivu je aldehyd trans-2-nonenal. Mechanismus vytvoření trans-2-nonenalu v pivu je enzymatická nebo neenzymatická oxidace tuků a oxidace volných mastných kyselin (obr. 1), kde svou roli sehrává enzym lipoxygenasa [1, 2].Vzhledem k tomu, že mastné kyseliny obsažené v obilce ječmene a následně ve sladu mohou být zdrojem mnohých senzoricky aktivních látek v pivu, bylo nutné zavést a optimalizovat stanovení tuků a mastných kyselin ve výchozích surovinách.Obsah lipidů byl stanoven pomocí moderní metody extrakce na fluidním loži. Pro analýzu zastoupení mastných kyselin byly porovnávány dvě polární kapilární kolony Supelcowax a SLB-IL 100. EXPERIMENTÁLNÍ ČÁST Použité chemikálie a standardyPetrolether -Lach-Net, s. r. o., ČR; izooktan -Sigma-Aldrich, USA;
The main problems of crop gene banks comprise heterogeneity of accessions, resulting from mechanical admixtures or out-crossing during their multiplication, and especially the mislabeling of accessions. These discrepancies can adversely affect the results of many expensive research and breeding projects that are based on the use of gene bank resources. To tackle these problems, 860 single-plant progenies (SPPs) of 172 accessions of the Czech winter barley core collection were grown and tested with a set of 53 isolates representing the global virulence/avirulence diversity of powdery mildew. Seventy-one resistance phenotypes encompassed the diversity of known specific resistances and their combinations. Based on testing groups of five SPPs, 94 accessions had one phenotype found in all five SPPs (homogeneous accessions), whereas in 78 accessions (45.3%) more than one phenotype was identified (heterogeneous accessions). In three varieties, specific resistances against the whole set of isolates were detected, but due to high adaptability of the pathogen, they are not recommended for breeding resistant cultivars. Selected SPPs were integrated in the gene bank and are now a reliable source of genotypically pure seed with defined powdery mildew resistance genes that can be used by breeders and researchers. The results obtained can be used to verify authenticity of accession genotype and pedigree, particularly for older varieties for which no other original criteria are available.
1 ÚVODObilky ječmene obsahují dva typy lipidů: zásobní a funkční. Zásobní lipidy, speciálně triglyceridy slouží jako zásobárna energie při mobilizaci specifických enzymů při poškození, nákaze a dalších stresují-cích faktorech nebo při klíčení. Když jsou zrna ječmene poškozena nesprávným skladováním nebo jsou vystavena určitým mikroorganismům, může dojít k degradačním reakcím lipidů. Tyto reakce mohou být katalyzovány vlastními endogenními enzymy zrna nebo enzymy mikroorganismů v závislosti na environmentálních podmínkách nebo poškození. Lipasa a lipoxygenasa jsou dva hlavní enzymy ovlivňující degradaci lipidů v zrnech ječmene [1].Hydrolýza triglyceridů je katalyzována lipasami, které jsou v zrnu vždy přítomné. Mezi nepříznivé efekty jejich aktivity patří především změny v chuti a aroma potravin, rostoucí acidita olejů a uvolnění nenasycených mastných kyselin, které jsou oxidovány lipoxygenasami [1,2].Specifickým substrátem lipoxygenasy je cis,cis-1,4-pentadiennová struktura, kterou je možno nalézt u mastných kyselin jako je linolová, linolenová nebo arachidonová kyselina, degraduje je buď na volné kyseliny, triglyceridy nebo methyl (ethyl) estery. Primární produkty jsou opticky aktivní cis-trans-konjugované hydroperoxidy. Tyto hydroperoxidy jsou tvořeny radikálovým mechanismem a jsou buď rozloženy, nebo dále oxidovány na sekundární produkty jako jsou alkoholy, kyseliny, ketony nebo aldehydy, které mohou nepříznivě ovlivnit nutriční hodnotu, aroma, chuť a kvalitu potraviny [1,2].Keywords: barley, beer, gas chromatography, malt, SPME, trans-2-nonenal 1 INTRODUCTION Barley caryopses contain two types of lipids: storage and functional. Storage lipids, especially triglycerides, serve as a reservoir of energy for mobilization of specific enzymes at damage, infection and other stress factors and during germination. Lipid degradation reactions can occur when barley grains are damaged by incorrect storage or exposed to certain microorganisms. These reactions can be catalyzed by endogenous enzymes of the grain or the enzymes from microorganisms depending on the environmental conditions or damage. Lipase and lipoxygenase are two principal enzymes affecting the degradation of lipids in barley grains [1].Hydrolysis of triglycerides is catalyzed by lipases which are always present in a grain. Adverse effects of their activity then include changes in food taste and aroma, increasing oil acidity and releasing unsaturated fatty acids oxidized by lipoxygenases [1,2].Lipoxygenase reacts specifically only with cis, cis-1,4-pentadiene structures, which can be found in fatty acids such as linoleic, linolenic or arachidonic acids, it degrades them either to free acids, triglycerides or methyl (ethyl) esters. The primary products are optically active cis-trans-conjugated hydroperoxides. These hydroperoxides are formed by a radical mechanism and they are either degraded or further oxidized to secondary products, such as alcohols, acids, ketones or aldehydes which can have an unfavorable impact on a nutritional value, aroma, taste an...
Both spring and winter barley were sown after a forecrop of winter rape. Three registered model varieties of six row and two row winter barley reached in the period 1999-2001 significantly higher yield than three model varieties of spring barley. Two row spring and winter varieties produced significantly higher thousand grain weight (TGW) than six row winter barley. The resistance to diseases and lodging (correlation coefficient with resistance to powdery mildew represent 0.68 ** , rust 0.72 ** , lodging 0.61 ** ) was the most important factor determining the yield. Resistance to rust has influenced sieving on 2.5 mm, correlation coefficient reached value 0.88 ** . No significant differences were determined in any malting quality parameter when varieties of two row winter barley variety (Tiffany), and spring barley varieties (Akcent and Tolar) were compared. Variety Tolar reached higher parameters for friability and a beta glucan content. Between years, significant differences were found in following parameters: protein content and apparent degree of attenuation. Due to reduction of area sown with spring barley and reduced yield potential, two row winter barley varieties with comparable malting parameters are recommended to be cultivated as the reserve crop for malting barley industry demands.
Nesvadba Z., Špunar J., Kadlíková M. (2013): Fabian two-row winter barley. Czech J. Genet. Plant Breed., 49: 175-177.Fabian is a medium-late two-row feedin barley of winter habit developed at Agrotest Fyto, Ltd., Kroměříž, Czech Republic (breeders' rights holder) and registered in the Czech Republic in 2011. In the Official Variety Trials it showed high grain yields under intensive growing conditions (104.5%) and medium yields under low input conditions (101.1%). Fabian has the highest cold hardiness of the registered two-row winter barleys and regenerates very well in the spring. Its resistance to powdery mildew is very high (score 8.2 on a 1-9 scale). It has medium plant height, moderate resistance to lodging and large yellow kernel. The spike is long and of medium density.
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