The purpose of this study is to explore the history and production processes of beer and examines the components that contribute to its brewing. The narrative will provide a timeline of the processes that are required to create the product of beer beginning with the agricultural products and following the brewing processes that result in beer as the finished product. I will also examine the business of agriculture and grain processing and will provide some historical perspectives of grain, beer, and malting. I will also consider whether the growing, processing, and malting of grains in the East Tennessee and Southwest Virginia Region is feasible as demonstrated through this research and reported findings.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Barley malt is the predominant raw material for beer brewing world-wide. To meet consumer demand, a constant high quality malt product is required. Malt quality is determined by the degree of substrate hydrolysis during germination and mashing which serves as fermentable substrates for alcoholic fermentation during brewing. It is often difficult to sustain malt of high quality due to inconsistent malt batches and poor germination capacities of dormant barley. External additives such as chemicals and gibberellic acid have been used to overcome these difficulties but are unwanted in the beverage industry. Maltsters are consequently always in search of alternative solutions. Microbes produce diverse enzymes which can contribute to substrate hydrolysis during germination. The development of such starter cultures might provide a natural and economically feasible alternative to augment barley germination. Starter culture technology has been employed in the malting industry, although the main focus has been to improve the microbial stability of malt. The exploitation of cultures with hydrolytic capabilities to augment barley germination is consequently largely unexplored. The aim of this study was to develop a starter culture which can contribute to the enzymatic degradation of barley polymers. Geotrichum spp. and Lactobacillus plantarum were isolated from substrates rich in polymers present in barley and screened for enzymatic capabilities. Geotrichum spp. produced cellulase, xylanase, protease and β-glucanase activities, while L. plantarum harboured cell-bound and extracellular α-amylase activities. These cultures were added in different combinations during the malting of Erica and SSG 564 cultivars, but did not enhance germination significantly. Improved malt parameters did not correlate with microbial enzyme activities and the data were not repeatable. Preliminary plate assays could thus not be used to predict enzyme production in a malting environment. Cell-free supernatants with known enzyme activities of Aspergillus sp., Trichoderma reesei and Rhizopus sp. significantly enhanced malt quality. To our knowledge, the use of fungal supernatant to augment malt modification is a novel concept. Supernatant is more convenient than starter cultures and will aid to deliver more constant malt products than live cultures, as known enzyme levels are added. / AFRIKAANSE OPSOMMING: Garsmout is wêreldwyd die oorheersende roumateriaal vir bier brou. Om die aanvraag van verbruikers te bevredig, word 'n konstante hoë gehalte mout produk vereis. Die kwailiteit van mout word bepaal deur die graad van substraathidrolise gedurende ontkieming, wat dien as fermenteerbare substraat vir alkoholiese fermentasie tydens verbrouing. Dit is dikwels moeilik om ʼn konstante, hoë gehalte, moutproduk te lewer as gevolg van variasie in mout en die swak ontkiemingsvermoë van dormante gars. Hierdie probleem kan oorbrug word met eksterne toevoegings soos chemikalieë en gibberelliensuur, maar dit is nie ʼn gewensde praktyk in die broubedryf nie. Vermouters is gevolglik gedurig op soek na alternatiewe oplossings. Mikroörganismes produseer diverse ensieme wat kan bydra tot substraathidrolise gedurende ontkieming. Die ontwikkeling van sodanige suurselkulture is moontlik 'n natuurlike en ekonomies praktiese alternatief om die ontkieming van gars te stimuleer. Suurselkulture is reeds in die moutindustrie gebruik, alhoewel die fokus hoofsaaklik was om die mikrobiese stabiliteit van mout te verbeter. Die konsep om kulture met hidrolitiese vermoëns te gebruik om garsontkieming aan te vul is gevolglik grootliks onverken. Die doel van hierdie studie was om 'n suurselkultuur te ontwikkel wat kan bydra tot 'n ensiematiese afbraak van die polimere in gars. Geotrichum spp. en Lactobacillus plantarum is uit substrate ryk aan polimere teenwoordig in gars geïsoleer en vir hul ensiem aktiwiteite getoets. Geotrichum spp. het sellulase, xylanase, protease en β-glukanase aktiwiteit getoon, terwyl L. plantarum sel-gebonde en ekstrasellulêre α-amilase aktiwiteit getoon het. Hierdie kulture is in verskillende kombinasies tydens die vermouting van Erica en SSG 564 kultivars bygevoeg, maar het nie tot ʼn verbetering in die ontkieming van die gars gelei nie. Geen korrelasie is gevind tussen verbeterde mout parameters en mikrobiese ensiemaktiwiteit nie. Die resultate was ook nie herhaalbaar nie. Voorlopige plaattoetse kan dus nie as 'n maatstaf gebruik word om ensiem produksie deur suurselkulture in vermounting te voorspel nie. Sel-vrye supernatante van Aspergillus sp., Trichoderma reesei en Rhizopus sp., met bekende ensiem aktiwiteit, het die gehalte van mout aansienlik verbeter. Sover ons kennis strek is die gebruik van supernatante van fungi om die ontkieming van gars te stimuleer ʼn nuwe konsep. Supernatant is meer gerieflik as suurselkulture en sal help om konstante mout produkte te lewer aangesien ensiemvlakke beter beheer kan word.

Ce travail s'intéresse au recyclage des rejets d'eaux usées par les malteries, principalement à l'étape de trempe. L'impact négatif de ces eaux sur la qualité des malts a été mis en évidence: leur réutilisation provoque un retard de prise d'eau par le grain et un retard de la germination. Puis, la caractérisation de ces eaux de trempe a permis d'identifier les inhibiteurs de la germination: il s'agit des intermédiaires d'oxydation et de polymérisation des composés phénoliques. Enfin, un procédé de traitement de ces eaux de trempe par bioréacteur à membrane a été mis au point. Testé aux échelles de laboratoire et pilote - avec ou sans couplage à une étape d'osmose inverse ou de charbon actif - ce procédé s'est révélé efficace pour l'épuration de l'eau et l'élimination des inhibiteurs. La réutilisation de ces eaux traitées dans l'étape de trempe n'a pas eu d'impact sur la qualité du procédé de maltage, et les malts ainsi préparés ont permis d'obtenir des bières de qualités équivalentes / This work is focused on the reuse of malting process wastewaters, especially steep-out waters. The negative impact of these waters on malt quality was demonstrated: their reuse results in a water uptake delay and a germination delay. Then, the characterisation of these steep-out waters allowed to identify germination inhibitors: they are intermediates of oxidation and polymerisation reactions of phenolic compounds. Finally, a membrane bioreactor treatment process of steep-out waters was developed. Studied at laboratory and pilot scales - with and without coupling to reverse osmosis or activated carbon step - this process was efficient for water treatment and for the removal of inhibitors. The reuse of these treated waters at the steeping step didn't have any negative impact on the process performances,and malts obtained allowed to prepare beers of comparable qualities

This Master thesis deals with the yield management evaluation and malting quality of chosen varieties of the spring malting barley in terms of half-working experiment in company "Kantor Václav - Agricultural businessman". There was chosen a stand of experiment and the values of yield management were observed, especially the number of plants, their offshoots and spikes per square unit, the quantity of grains in spikes, the weight of a thousand seeds and the yield. In case of the grain quality elements was rated a content of nitrogen substances, the drop above the sieve 2,8, 2,5, 2,2 mm and under the sieve 2,2 mm, then the content of amyloid, germination and its energy as well as the grain moisture. Among the rated varieties were placed: Malz, Sebastian, Laudis 550, Kangoo, Xanadu, Sunshine, Bojos, KWS Irina and Pionier. The results were filed in the tables and charts. The influence of variety on a different yield element was found out in the final comparison of all parameters. According to the aspect of the yield elements as well as the quality, the best values in this year taking experiment were reached by the Kangoo variety.

Licentiatavhandling (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 2 uppsatser.

Thesis (MScFoodSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The potential malting, brewing and antiyeast characteristics of twelve selected sorghum cultivars from Zambia (MMSH 375, 625, 707, 1038, 1077, 1194, 1257, 1356, 1363, 1365, 1376 and 1401) was evaluated. This was done through the determination of tannin content, proximate composition, %germinative energy (%GE), micro-structure, diastatic power (DP) and free amino nitrogen (FAN); as well as the antiyeast activity of N-containing compounds for each cultivar. All cultivars were tannin-free and thus suitable for brewing potential exploration. Seven cultivars (MMSH-375, 625, 1038, 1194, 1257, 1401 and 1376) had a %GE considered appropriate for malting and brewing. A maximum of 25% of the DP level recommended for commercial malting was achieved in this study. In spite of the low DP observed in all cultivars after malting, high extract levels ranging between 18.7 and 25.5˚P were achieved. In unmalted grains a significantly FAN level (p≤0.05) was observed in three cultivars (MMSH-375, 1194 and 1077). These FAN values, however, represented less than 10% of the recommended FAN level necessary to support proper yeast functioning during wort fermentation. The 150 mg/L threshold which is necessary to support proper yeast function and is employed in modern day brewing was achieved in malts of sorghum cultivars MMSH-375 (intermediate cultivar) and 1401 (intermediate cultivar). A FAN level between 100 and 140 mg/L, which is considered enough to support optimal fermentation, was achieved in cultivars MMSH-625 (intermediate cultivar), 1077 (hard cultivar), 1194 (intermediate cultivar), 1356 (soft cultivar) and 1376 (intermediate cultivar) after malting. Mashing did not significantly increase FAN levels in all sorghum cultivars. The addition of potassium metabisulphite (KMS) in the mash did, however, lead to a further increase of FAN levels in all cultivars. Scanning electron micrographs revealed that the corneous endosperm was inaccessible to degradation by enzymes and only the soft endosperm was modified in all cultivars during malting. The N-containing compounds from selected malts of sorghum cultivars with good malting and brewing potential (MMSH-375, 625, 1401 and 1194) were isolated and their antiyeast activity was determined. It was found that the N-containing compounds were playing an essential role during fermentation by contributing positively towards yeast growth in all four cultivars. However, a 20-30% reduced growth at the lower concentrations of the putative %yeast growth promoting N-containing compounds was observed in all cultivars. Irrespective of the reduced %yeast growth observed in all four cultivars at low concentrations of the putative yeast growth N-containing compounds, it could not be concluded that the sorghum cultivars utilised in this study possess antimicrobial peptides and proteins because only small compounds (<1 kDa) were detected with UPLC-MS. The dose-response data showed that extracts of MMSH-375 and MMSH-625 resulted in generally a higher %yeast growth when compared to other cultivars. The UPLC-MS also confirmed the dose response data that MMSH-375 has a better qualitative yeast-feeding value. MMSH-375 is thus rated as the best cultivar out of the four that were screened and is recommended to be use in the commercial production of sorghum lager beer. / AFRIKAANSE OPSOMMING: Die potensiële mout, brou en teen-gis eienskappe van twaalf geselekteerde Zambiese sorghum kultivars (MMSH 375, 625, 707, 1038, 1077, 1194, 1257, 1356, 1363, 1365, 1376 en 1401) was geëvalueer. Dit is gedoen deur die bepaling van tannien inhoud, proksimale samestelling, % ontkiemings energie (%OE), mikrostruktuur, diastatiese krag (DK) en vrye amino stikstof (VAS) inhoud; sowel as die teen-gis aktiwiteit van stikstofbevattende verbindings vir elke kultivar. Alle kultivars was tannien vry en dus geskik om te ondersoek vir brou potensiaal. Sewe kultivars (MMSH 375, 625, 1038, 1194, 1257, 1401 en 1376) het ‘n %OE geskik vir mouting en brouery gehad. ‘n Maksimum van 25% van die voorgestelde DK vlak vir kommersiële brouery was gevind in hierdie studie. Hoë ekstrak vlakke van tussen 18.7 en 25.5˚P is gevind, ten spyte van die lae DK wat gevind is in alle kultivars na mouting. ‘n Betekenisvolle VAS vlak (p≤0.05) was gevind in die ongemoute graankorrels van drie kultivars (MMSH 375, 1194 en 1077). Hierdie VAS vlakke was egter minder as 10% van die voorgestelde VAS vlakke benodig om gis funksie te ondersteun tydens fermentasie. Die 150 mg/L drumpelwaarde benodig vir korrekte gis funksie en gebruik in moderne brouery is bereik in gemoute sorghum kultivars MMSH 375 (intermediêre kultivar) en 1401 (intermediêre kultivar). ‘n VAS vlak van tussen 100 en 140 mg/L, gereken as genoegsaam vir optimal fermentasie, was bereik in kultivar MMSH 625 (intermediêre kultivar), 1077 (harde kultivar), 1194 (intermediêre kultivar), 1356 (sagte kultivar) en 1376 (intermediêre kultivar) na mouting. Warm water weking het nie die VAS vlakke in die sorghum kultivars betekenisvol verhoog nie. Die byvoeging van kalium metabisulfiet (KMS) tot die weekvloeistof het egter gelei tot ‘n verdere verhoging van VAS vlakke in alle kultivars. Skandering elektronmikrograwe het aangedui dat die growwe endosperm ontoeganklik is vir ensiematiese afbraak en dat slegs die sagte endosperm van alle kultivars veranderinge ondergaan het tydens mouting. Die stikstofbevattende verbindings van die gemoute sorghum kultivars geselekteer op grond van hul goeie mout en brou potensiaal (MMSH 375, 625, 1401 en 1194) was geïsoleer en hul teen-gis aktiwiteit was bepaal. Daar was bevind dat die stikstofbevattende verbindings ‘n noodsaaklike rol speel tydens fermentasie deur ‘n positiewe bydrae tot gisgroei te maak in al vier kultivars. Verminderde groei (20-30%) was egter opgelet by laer konsentrasies van die vermeende groei-bevorderende stikstofbevattende verbindings in alle kultivars. Ten spyte van hierdie verminderde gisgroei by lae konsentrasies kon daar nie afgelei word dat die sorghum kultivars gebruik in hierdie studie wel antimikrobiese peptiede en proteïne bevat nie aangesien slegs klein verbindings (<1 kDa) waargeneem word met UPLC-MS. Die dosis-respons data het aangedui dat ekstrakte van MMSH 375 en 625 oor die algemeen gelei het tot hoër gisgroei in vergelyking met ander kultivars. UPLC-MS het ook bevestig dat MMSH 375 ‘n beter kwalitatiewe gisvoedingswaarde het. MMSH 375 word dus gereken as die beste kultivar uit die vier gekeurde kultivars en word aanbeveel vir gebruik in die kommersiële produksie van sorghum lager bier.

Tato práce se zabývá proteomickými studiemi ječmene v souvislosti s výrobou piva. Ječmen patří mezi nejvýznamnější plodiny na světě a je využíván hlavně pro sladovnické účely, nejčastěji pro pivovarnictví. Studium proteinů ječmene během sladování a výroby piva poskytuje informace o změnách v proteinovém složení nebo jejich posttranslačních modifikacích. Jelikož jsou proteiny v ječmeni a jejich změny zásadní pro kvalitu sladu a piva, proteomické studie ječmene mají potenciál pro zlepšení procesu sladování a pivovarnictví. Hlavním cílem této práce je studium ve vodě rozpustných proteinů ječmene a jejich změn, ke kterým dochází během sladování a výroby piva. Rozdíly v proteinovém složení byly sledovány pomocí gelové elektroforézy, kapalinové chromatografie na reverzní fázi, gelové chromatografie a MALDI-TOF hmotnostní spektrometrie. Během sladování se vlivem klíčení zrna zvyšuje množství některých proteinů a také jsou tvořeny nové proteiny. V průběhu vaření piva se naopak v důsledku vysoké teploty a enzymatické aktivity proteáz mnoho proteinů rozkládá. Těmto drsným podmínkám odolají jen některé proteiny, které přechází až do piva a mohou ovlivnit jeho kvalitu. Dále byly zkoumány různé odrůdy ječmene a jejich rozdíly. Byly porovnány odrůdy povolené pro výrobu certifikovaného Českého piva s jednou osvědčenou sladovnickou odrůdou a jednou nesladovnickou odrůdou ječmene. Kromě toho byly studovány v alkoholu rozpustné proteiny ječmene a jejich změny v průběhu sladování. Zvláštní pozornost byla věnována vybrané skupině posttranslačních modifikací proteinů: glykosylacím. Neenzymaticky glykosylované proteiny ječmene (neboli glykované proteiny) jsou tvořeny v průběhu sladování kvůli přítomnosti velkého množství glukózy uvolněné z rozkladu škrobu. Glykované proteiny ovlivňují stabilitu proteinů a kvalitu piva, obzvlášť pěnotvorný účinek. Enzymatické N-glykosylace představují nejčastěji studované posttranslační modifikace u rostlin, protože glykoproteiny hrají klíčovou roli v různých biologických funkcích. Glykoproteiny jsou často přítomny v malém množství, a proto je pro jejich analýzu potřebné obohacení glykoproteinů z komplexní směsi. Pro studium glykoproteinů byla využita afinitní chromatografie s lektinem concanavalin A. Kromě toho byla také optimalizována analýza sacharidové části glykoproteinů. Tato disertační práce přináší důležité informace o proteinech ječmene, jejich změnách a analýze, které budou užitečné pro další studium.

The aim Master thesis was to evaluate the influence of malting technology on the content of hydrolytic enzymes -amylase and -amylase. Another aspect of this thesis was to select a wheat variety with the highest activity of enzymes -amylase and -amylase. The first part of the practical part of my work is shown measuring enzyme malt model varieties of wheat set (Triticum aestivum), where individual samples differ technological processing of malting and the second part is focused on the application of efficient malting conditions on other varieties from different locations in the Czech Republic in 2016 . All malt samples were analysed to -amylase and -amylase activity by assay Ceralpha method and Betamyl-3 method made by Megazyme company. After measuring the first part, the most effective malting condition was evaluated, such as a 7 day malting time, a 45% water content, a germination temperature of 18 ° C, and a drying temperature of 50 ° C. In the second part, the varieties are so malted and the highest content of enzyme -amylase was Rumor, it had averafe contanin -amylase 277 U/g, Bonanza – 255 U/g and Izzy –254 U/g. The biggest contain of enzymes -amylasehad varieties Matchball – 37,9 U/g , Fakir – 35,6 U/g, and Bernstein – 35,3 U/g.

Wheat (Triticum aestivum, L) and barley (Hordeum vulgare) are widely grown as winter annual grains in a double crop rotation with soybean (Glycine max, L. Merr.) in much of the U.S. Improved management strategies and the development cultivars that meet the quality requirements of higher value end-use markets is important to increase production and profitability of winter annual grains and the double crop rotation in the Eastern U.S. In Chapter I, fifteen commercially relevant winter wheat genotypes ranging in maturity were sown in a split-plot design (sowing date=main plot, genotype=subplot) at three different sowing dates (considered to be 'very early' (20-28 days before recommended), 'early (6-11 days before recommended)', or 'recommended') and replicated three times at eight environments (site-year) from 2015-2018 in VA and KY. Grain yield, tiller estimation, heading date, protein, and 1000-kernel weight were assessed for each yield plot. At all environments, sowing earlier in the fall achieved an earlier (P<0.05) heading date, while grain yields varied depending on environment and genotype. Genotype by sowing date interactions were non-significant (P<0.05) at five site-years and significant (P<0.05) at three site-years. Molecular markers can be associated with phenotypic traits via quantitative trait loci (QTL) mapping, these markers can be used by breeders in marker assisted selection (MAS) to indirectly select phenotypic traits that are difficult or expensive to measure. In Chapter II, the genetic architecture of end-use quality is investigated in two soft red winter wheat bi-parental (Pioneer '25R47' / 'Jamestown' and Pioneer '26R46' / 'Tribute'). Both populations were genotyped with a public 90,000 wheat iSelect SNP-Array, grown over two crop seasons at two Virginia sites, evaluated for quality traits at the USDA-ARS Soft Wheat Quality Lab (SWQL), and analyzed with QTL mapping. This chapter describes a total of 24 putative QTL that were identified on 13 different chromosomes and associated with grain characteristics, milling, and/or baking performance along with phenotypic data for both populations, other putative QTL, and transgressive progeny with exceptional flour yield and cookie diameters. A region on 3A (Qfy.vt.3A.Jtwn) is a strong candidate to be utilized for MAS in soft red winter wheat breeding programs as it explained 6.9-10.3% (Pioneer 25R47 / Jamestown) and 4.6-17.0% (Pioneer 26R46 / Tribute) of the phenotypic variation for flour yield. In Chapter III, malt quality genetic structure was investigated in two winter 'malt x feed' doubled haploid barley breeding populations. Both populations were genotyped with the iSelect InfiniumTM SNP assay consisting of 50,000 barley SNPs, grown in two to three Virginia environments (Blacksburg and Warsaw) during 2017 - 2019, and characterized for 11 phenotypic traits associated with malting quality. QTL mapping validated six previously reported regions (Mohammadi, et al., 2015, GrainGenes 3.0, 2019) that are strongly associated (LOD > 3.0) with relevant malt quality traits. Phenotypic variation for malt quality was largely and consistently explained by QTL on chromosomes 1H, 5H, and 7H in the Endeavor / VA09B-34 population and by two separate QTL on 1H in the Violetta / VA09B-34 population. A region on 4H corresponding with QDp.DiMo-4H, explained between 12.1 - 42.2% (Endeavor / VA09B-34) and 30.0 - 55.7% (Violetta / VA09B-34) of the phenotypic variation for diastatic power (DU). These QTL are recommended for MAS in order to aid breeding strategies that aim to select for improved malting characteristics in Eastern U.S. malt barley breeding material. / Doctor of Philosophy / Wheat (Triticum aestivum, L) and barley (Hordeum vulgare) are staple crops throughout the world, and are the third and fourth most produced cereals crop according to the FAO. Primarily grown for human consumption, wheat and barley provide a significant percentage of the nutritional requirements for the human populations. According to the United Nations, wheat contributes 20% of all calories consumed by humans. Barley is the primary ingredient used to make beer. Increased productivity of all cropping and livestock systems is required in order to feed a growing human population while also restoring and preserving natural ecosystems. This can be accomplished through breeding and improved cropping systems management. Planting of existing cropland more frequently is fundamental to the improvement of cropping system productivity. In much of the U.S. (southern two-thirds of the lower 48), annual winter grains such as wheat and barley can be grown over the winter and spring in between the typical corn (Zea mays subsp. mays) and soybean (Glycine max, L. Merr.) growing seasons. Therefore, producing three crops in two years, as opposed to only two. Only between 6 and 11 million acres are double cropped in the US annually, for perspective, in 2018, 89 million acres of both corn and soybeans, which can only grow in summer, were planted. Over half of the soybean (~45 million) acres in Midwestern and Southeastern states could support double cropping. This is a major opportunity to maximize output per unit area, freeing up less productive land to be restored as natural ecosystems, potentially increasing carbon sequestration and species biodiversity. Winter annual grains have a very similar composition (high carbohydrate, low protein and oil) to corn, and could fill similar end-use markets currently dominated by corn (i.e. ethanol or livestock feed). For double cropping to be more widely deployed, it must be more profitable. Increased profitability of growing three crops in two years as opposed to two must outweigh the added cost of planting, managing, harvesting, and marketing the additional winter crop. Therefore, it is important to investigate management strategies that could increase production per unit area and develop new winter annual cultivars with improved end-use characteristics in order to make the winter annual more desirable to the end-users. Chapter I investigates sowing winter wheat earlier in the fall (i.e. 1st week of Oct. or last week of Sept.) in order to achieve an earlier harvest in the spring and earlier soybean planting (yield decreases 0.5 to 1 bu/ac per day that sowing is delayed), while also offering other benefits such as better-established root systems going into winter, which improves water infiltration and reduces erosion. At all environments, sowing earlier in the fall achieved an earlier heading date, while grain yields varied depending on environment and genotype. Genotype by sowing date interactions were non-significant at five site-years and significant at three site-years. Chapters II and III investigate the genetic architecture of winter wheat and winter barley breeding populations for end-use quality traits (milling/baking and malting). This was done in order to identify molecular markers that could be used to screen breeding material for improved end-use quality. The markers could then be used to assist breeders in developing soft red winter wheat cultivars with greater flour yields/improved baking performance and winter malt barley cultivars that can be grown in the Eastern U.S. and are suitable for the craft beer market. Chapter II describes 24 genomic regions that influences milling/baking performance in two soft red winter wheat breeding populations. Chapter III describes 6 genomic regions that influence malting performance in two winter barley breeding populations.

Résumé : Chez lorge, la dégradation des polysaccarides des parois cellulaires et de lamidon est de première importance dans le contexte de sa valorisation brassicole. La présente recherche doctorale a été entreprise dans le but didentifier des marqueurs de sélection utilisables lors de lamélioration génétique de lorge de printemps pour ses qualités brassicoles. Des gènes candidats ont dabord été choisis sur base de leur expression dans les tissus de la graine en germination. Leur position cartographique a été déterminée et située par rapport à des marqueurs QTL connus de la qualité brassicole. Exploitant des variétés cultivées de qualités contrastées, une recherche de polymorphismes nucléotidiques au niveau de ces gènes a été réalisée. Tous les gènes savèrent polymorphes, certaines des variations de séquence conduisant à des modifications de la structure primaire de la protéine encodée. Plusieurs caractères technologiques ont été retenus et définis chez les variétés étudiées, en exploitant les données de la littérature : la teneur en extrait, la viscosité, la teneur en β-glucanes du mout, latténuation finale apparente et le pouvoir diastasique. Plusieurs caractères biochimiques ont été étudiés chez ces mêmes variétés et ont ciblé quatre activités enzymatiques impliquées dans la dégradation des polysaccharides pariétaux et de réserve. Le pouvoir discriminant et la simplicité du test dactivité amylase, ainsi que sa relation avec des critères technologiques importants, en font un test prometteur en vue de faciliter la sélection variétale. La relation entre les sites polymorphes de lADN et les caractères technologiques et biochimiques identifient une soixantaine de sites dont les polymorphismes semblent associés à au moins lun des caractères. Sur tous les sites polymorphes, treize sites sont choisis pour leur potentiel en tant que marqueurs de sélection. Ils distinguent en effet un allèle favorable et un allèle défavorable pour plus dun critère brassicole. Ces treize sites sont localisés sur des gènes de (1-3,1-4)-β-glucanase, un gène de (1-3)-β-glucanase, un gène de (1-4)-β-xylan endohydrolase et un gène dα-amylase. La mise en évidence de ces allèles peut être réalisée par des tests PCR simples (« allèles spécifiques ») et relativement peu coûteux, dont six ont été mis au point au terme de la recherche./ Summary: In barley, the degradation of cell wall polysaccharides and starch is of utmost importance for its malting quality. The aim of this thesis is the identification of selection markers useful in the breeding of spring Barley cultivars for improved malting quality. Candidate genes were first chosen based on their expression profile in tissues of germinating seeds. Their mapping positions were determined and compared with known QTLs for malting quality. Varieties with contrasted malting qualities were searched for DNA polymorphisms for each of these genes. All genes proved to be polymorphic, some of the sequence variations leading to changes in the primary structure of the encoded protein. Technological traits were chosen and used to characterize the varieties based on literature data: extract yield, viscosity, β-glucan content of the wort, final apparent attenuation and diastatic power. Biochemical traits were also investigated on the same varieties and focused on four enzyme activities implicated in cell wall polysaccharides and starch degradation. The Discriminant power and ease of the amylase test, as well as its relation with technological traits, make it a promising selection test in breeding programs. The relationship between the DNA polymorphisms and biochemical and technological traits reveals around sixty polymorphisms displaying apparent relationships with at least one trait. Thirteen out of them were chosen for their potential as selection markers. They are located on (1-3,1-4)-β-glucanase genes, on one (1-3)-β-glucanase gene, on one (1-4)-β-xylan endohydrolase gene and on one α-amylase gene. Detection of these alleles can be achieved by simple and inexpensive PCR tests ( allele specific), and six assay protocols have been set up at the completion of this research.