Please read the abstract in the section 00front of this document / Thesis (DPhil (Food Science))--University of Pretoria, 2007. / Food Science / DPhil / unrestricted

Labeling of malt beverages is impacted by multiple entities, both regulatory and industry. The entity with the most overt impact is the Alcohol and Tobacco Tax and Trade Bureau (TTB), which defines and regulates the following items: 1) required label components for beverages that meet the TTB’s institutional definition of “malt beverage”, and 2) the formula approval process for malt beverages required to undergo the pre-Certificate of Labeling Approval (COLA) evaluation. In order for producers of malt beverages to sell their products in interstate commerce, they must first satisfactorily complete the Certificate of Labeling Approval (COLA) process. For products that are created using “nontraditional” processes or ingredients, producers must also complete a formula submission prior to completing the COLA process. The substantial growth of the craft brewing industry has resulted in a corresponding increase in the submission volume of COLAs and formula approvals. The increased workload of TTB officials responsible for processing approvals, coupled with intense industry focus on innovation, has resulted in a complicated interchange between industry and government. Using three studies, this research evaluates the craft brewer experience with the TTB’s COLA and formula approval processes.The first study was a qualitative research study conducted to explore craft brewers’ perceptions of regulations related to the COLA and formula approval processes. Using convenience sampling, 13 interviews were conducted with craft brewers from August 2018 to December 2018. All interviews were conducted using a semi-structured interview guide and analyzed using a thematic approach. The findings indicate that formula and labeling approval presents unique challenges to craft brewers. Participants associated with small and large craft breweries identified opportunities for improved communication between the craft brewing industry and the TTB. The data collected also indicate that that there exist opportunities to improve existing resources for brewers as they pertain to labeling and formula approval.The second study evaluated the role of brewery characteristics in brewer preparation of COLA and formula submissions. Using survey data, the relationship between brewery characteristics and regulatory submission outcomes was evaluated. The brewery characteristics of interest were number of full-time personnel, permit age, production volume, and COLA and formula submission volume. The submission outcomes evaluated were information burden, expense burden, and resubmission frequency of COLA and formula approvals. The results indicated that production volume significantly predicts one measure of information burden (regulatory navigation) related to COLA preparation: the data suggests that as production volume increases, information burden decreases. In addition, submission volume of formulas was significantly related to one measure of information burden (regulatory navigation), with decreased information burden occurring alongside increased submission volume. Expense burden and resubmission frequency were not significantly predicted using any of the studied brewery characteristics.The third study examined the role of resource utilization in regulatory submission outcomes (expense burden, information burden, resubmission frequency). Using survey data, the relationship between the volume and type(s) of resources used during submission preparation and submission outcomes was evaluated. The resources of interest were: the TTB website, the Brewers Association website, advice from a fellow brewer, advice from a coworker or boss, correspondence with TTB officials, and (in formula submissions) the TTB Exemption List (Attachment 1 of TTB Ruling 2015-1) .The results indicate that advice from a boss or coworker reduced expense burden of COLA submissions, while advice from a fellow brewer was associated with decreased expense burden of formula submissions. In addition, advice from a fellow brewer, correspondence with TTB officials, and use of the Brewers Association website were all associated with decreased information burden of COLA submissions. Information burden associated with formula submissions was significantly predicted using advice from a fellow brewer and advice from a boss and/or coworker. Resubmission frequency of formula submissions was significantly predicted using correspondence TTB officials.

Volatile sulphur substances originating during technological processes in malt and beer production can be a cause of various off-flavors and aromas. Their precursors are sulphur-containing amino acids. Sulphur substances play an important role in brewing as even in very low concentrations they can negatively affect total character of beer. Therefore, it is necessary to monitor volatile sulphur substances and their precursors to eliminate undesirable processes. Because sulphur substances occur in beer and raw materials at trace levels, microanalytical methods are used for their detection. This diploma thesis describes the problems of sulphur substances and their determination using the SPME/GC method.

Although sorghum malt is relatively rich in free amino nitrogen (FAN), the 150 mg FAN/L threshold recommended for brewing is difficult to obtain. The vitreous nature of the sorghum endosperm hinders proteolysis during brewing. Hence, exogenous proteolytic enzymes are often required to increase hydrolysis of sorghum malt protein to produce sufficient FAN in order to support rapid yeast growth during fermentation. Ten exogenous proteases were examined for their production of FAN in sorghum malt mashing. Mashing was done at 550C for 45 minutes. Levels of FAN, as determined by the ninhydrin method, showed great variation among the proteolytic enzymes, ranging from 96 in control to 182 mg/100 g malt with possibly of most effective proteolytic enzyme. The variation in FAN level was possibly due to different optimal mashing conditions of exogenous proteases used and perhaps due to low ratios of exopeptidase/endopeptidase in the enzyme preparations. Low temperature (400C) and long duration mashing for (7 hours) gave good FAN production during mashing to a total of 113 and 138 mg/100 g malt in control and the treatment with exogenous proteolytic enzyme Flavourzyme plus malt, respectively. The exogenous enzyme (Flavourzyme) plus potassium metabisulphite (PMB) increased FAN production during mashing in the ratio of 2 to 1 in a treatment where PMB was added compared to one without. Similarly, hot wort extract (HWE) increased by 8% during mashing with exogenous enzyme plus PMB compared to one without PMB, respectively. PMB was involved in destabilizing the disulphide bonds in the sorghum protein polypeptide chains allowing proteolytic enzymes better accessibility to proteins. The increase in HWE was possibly due to the starch being freed from the sorghum protein matrix. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed some oligomeric and polymeric kafirins after mashing. With transmission electron microcopy (TEM), protein bodies of varying sizes with partially degraded peripheral edges and some holes were seen after mashing. SDS-PAGE and TEM results suggest insufficient proteolysis. High protein digestibility sorghum’s potential for brewing was examined with reference to FAN production. Although during mashing FAN increased by approx. 82 and 115% for unmalted normal and high digestibility sorghums, respectively, the 150 mg FAN/L threshold, recommended for brewing was not achieved. FAN production to levels above 150 mg/L may only be realized if normal sorghum malt or high protein digestibility sorghum malt is mashed with exogenous enzymes containing sufficient exopeptidases coupled with appropriate mashing conditions. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Food Science / unrestricted

Master of Science / Food Science Institute, Grain Science and Industry / Jeffrey A. Gwirtz / There is a limited market of gluten-free beer for the 1% of the US population that is diagnosed with an autoimmune response to gluten protein known as celiac disease. Sorghum can be malted and used in the brewing process to replace malted barley, a grain toxic to celiac patients. The objective of the study was to develop an optimum brewing procedure for a gluten-free ale-style beer. Four different sorghum hybrids (82G63, 83G66, RN315, and X303) were malted and used in brewing gluten-free ale and evaluated for physical and chemical property differences. The four sorghum hybrids were characterized first as grain and then as malt using proximate analysis, single kernel characterization system (SKCS), amylose, α-amylase, and β-amylase contents. Isolated starch from unmalted and malted samples was evaluated with differential scanning calorimetry (DSC). Malt was evaluated throughout the malting process and percent nitrogen, percent moisture, 72 hr germinative energy, steep out moisture, germination-end, and malting loss were measured. Malted sorghum hybrid samples were milled into grist, and employed in a double mash, double decoction brewing process. Following the brewing process the wort was evaluated for specific gravity, Brix, pH, color and free α-amino nitrogen (FAN). Wort was also analyzed using HPLC for ethanol and glucose content. The fermented beer was analyzed for specific gravity, Brix, pH, alcohol by volume, and color. HPLC was also used to measure ethanol and glucose content. Results of analysis found that a significant difference (p=0.05) was found for the DSC data onset temperature, which ranged from 61.75 to 65.51, illustrating the difference in starch gelatinization temperature compared to other cereals. A significant difference was found in α-amylase content (p=0.05) which ranged from 0.16 to 058 in unmalted sorghum and 71.63 to 96.44 in malted sorghum. In addition, α-amylase and β-amylase contents increased during malting. HPLC analysis of wort indicated a significant difference was found in percent maltose which ranged from 1.27 to 2.81. FAN content of wort was also significantly different and ranged from 65.15 to 151.37. HPLC of beer showed a significant difference in percent ethanol and percent glucose. Percent ethanol in the final beer ranged from 3.28 to 4.17 and percent glucose range from 0.16 to 0.31. Process development evaluation indicated a gluten-free ale style beer could be successfully produced with 100% sorghum malt.

This thesis has reviewed two aspirationssystems at Viking Malt in Halmstad, Sweden. Based on this different optimization solutions has been developed for aspirationssystem 180 and 901. Viking Malt has several of plants and is the fifth largest producer of malt in Europe. As a company they constantly strive to be an energy efficient company to compete on the market. During 2015 over 200 00 ton of malt was delivered from the plant, enough to brew 1,6 billion liter of beer. From the corn reception to the finished malt, large portions of dust are created. This has to be taken care of to avoid danger of fire and to ensure a clean product. This is achieved by exhaust fans who aspirate the dusty air from the process steps where its needed, with big filters the dust is separated from the air. In the plant frequency converters are installed on aspirationsline 180 and 901 these are currently set to have the same max and min frequency, which means no speed control is currently active on the fans. The reason behind this is because consultants have not come up with any concrete solution proposals to Viking Malt so the issue has been put aside. To investigate the aspirationssystem and to clarify the problem with the frequency converters has measurements of airflow and tests with the frequency converters been done. Through treatment of earlier investigations of the aspirationssystem, discussion with the employees and new survey efficiency proposals has been identified. From calculations and investigations of the aspirationssystem three different options has been presented. The thesis has designed an action plan that Viking Malt may use as a tool to identify which option is the most relevant. / Examensarbetet har systemgranskat och bearbetat fram optimeringsmöjligheter på Viking Malts aspirationssystem på linje 180 och 901 i Halmstad. Viking Malt har ett flertal anläggningar i Norden och är Europas femte största maltproducent. Företaget strävar ständigt efter att effektivisera driften och kvalitén för att kunna vara konkurrenskraftig på marknaden. Under 2015 levererades över 200 000 ton malt från anläggningen vilket skulle räcka till att brygga 1 600 000 m3 öl. Från kornmottagning till färdigställd malt sker det stora dammbildningar som måste ledas bort för att undvika explosionsrisker och försämring av produktens kvalité. Detta uppnås med hjälp av frånluftsfläktar som aspirerar dammfylld luft ifrån processteg där behovet finns, och med hjälp av aspiration kan damm extraheras från luften. I anläggningen sitter det frekvensomformare på linje 180 och 901 som idag har samma max och min frekvens vilket betyder att det inte sker någon varvtalsreglering på fläktarna. Anledning till denna åtgärd är att aspirationen inte fungerar som den ska. För att undersöka aspirationsanläggningen och klargöra problematiken med styrningen har mätningar av luftflödet samt test av frekvensomformare utförts. Genom studera tidigare utredningar, ny kartläggning av aspirationslinjerna och diskussion bland personal har optimeringsförslag identifierats. Utifrån tryckfallskalkyler av aspirationslinjerna 180 och 901 har tre ändringsförslag presenterats. Examensarbetet har även utformat en handlingsplan som Viking Malt kan använda som ett verktyg för de åtgärder som blir relevant. Med implementering av något av de tre åtgärdsförslagen blir systemet anpassat efter erfordrat tryckfall, detta innebär att produktkvalitet kan säkerställas. Utöver detta finns det möjlighet till energibesparing upp till 23,2 MWh/år beroende av optimeringsåtgärd.

Le giclage de la bière est un phénomène de surmoussage qui a lieu lors de l’ouverture de la bouteille. Ce phénomène va être dépendant des conditions de développement du grain d’orge, la matière première de la bière, et notamment des conditions climatiques. Ces dernières années, le phénomène est observé de manière plus fréquente, et les techniques actuelles, comme la méthode Carlsberg, ne prédisent qu’un risque potentiel de giclage de la matière première avec une importante incertitude. Un test de criblage rapide de la matière première permettant l’identification de facteurs responsables du giclage est donc primordiale pour détecter précocement le risque de ce phénomène. Néanmoins, un manque d’informations et de recul sur les composés impliqués dans le giclage limite le développement de méthodes de prédiction rapide du risque. L’objectif principal de cette étude est d’identifier un ou des composés pouvant être à l’origine du phénomène de giclage de la bière. L’étude a été réalisée sur différents malts industriels présentant un risque giclage ou non et des orges artificiellement contaminées par des moisissures. Les extraits de malt obtenus sont des mélanges éminemment complexes. Ils ont été fractionnés par des procédés appropriés selon les propriétés de leurs constituants : par la taille, les propriétés moussantes et l’hydrophobie. Une réduction de la complexité de l’extrait a été nécessaire et obtenue par des techniques de séparation membranaire. Néanmoins, les macromolécules tels les glucides, les protéines et les polyphénols n’ont pas pu être isolés par ce procédé. La séparation par chromatographie de phase inverse a permis d’obtenir de bonnes informations sur la diversité des protéines présentes dans l’extrait mais l’analyse du potentiel giclage en aval reste limitée. Pour simuler des conditions réelles « comme au champ », une contamination artificielle de l’orge suivie d’une extraction en surface ont été réalisées. Le potentiel giclage des molécules issues de cette extraction a ensuite été analysé. Une purification de phase inverse a permis d’isoler une fraction concentrant les propriétés giclantes. Cette fraction contient des protéines très hydrophobes qui semblent être impliquées dans le giclage. L’identification des protéines après séparation en gel bidimensionnel a montré que ces protéines proviennent de la moisissure. Une protéine avec des propriétés proches des hydrophobines (hydrophobie et taille comparables) appelée Epl 1 a été identifiée et pourrait être un bon candidat responsable du giclage de la bière. En conclusion, la méthodologie développée dans la thèse a permis d’acquérir une meilleure connaissance des composés produits par les moisissures en surface d’orge et est applicable à d’autres orges contaminées ainsi qu’à du malt industriel / Beer gushing is an explosive over-generation of foam following the opening of a bottle. It is highly dependent on barley growing and harvesting climatic conditions and has been observed more frequently over the past years. Current technics, such as the modified Carlsberg test, only provide informations on a predictive gushing potential of malt with a large uncertainty. A rapid screening test on raw material leading to the identification of actual factor(s) responsible for the gushing is consequently highly required by the brewing industry. But a lack of informations about the compounds involved in gushing limits the development of such a technic. The initial goal of this study was to identify the compounds involved in beer gushing. This approach has been applied to industrial malts presenting gushing potential or not and artificially contaminated barleys in order to set a procedure to isolate compounds which may trigger gushing. In a first time, malt extracts, which are complex mixtures, have been produced and fractionated according to the properties of compounds such as their size, their foaming capacity or hydrophobicity. A good reduction of complexity of sample has been obtained after membrane filtration. Nevertheless, compounds like carbohydrates, proteins and polyphenols could not have been separated. Besides, separation by hydrophobicity has provided good information about the diversity of proteins but the analysis of their gushing potential remains difficult. Afterwards, in order to investigate the production of compounds by fungus at the surface of barley simulating real field crop production conditions, an artificial contamination was achieved and surface extraction with ultrapure water has been performed. Extracted molecules have been screened for their gushing activity. Thus, a purification of molecules by reverse phase chromatography allowed to isolate a gushing fraction from the surface extract. This fraction, which concentrates the gushing properties, is composed by proteins with high hydrophobicity which may be involved in gushing. This fraction was analyzed more in depth with a 2DE, and led to the identification of proteins all produced by fungus family. Among them, a protein called Epl1 appears to be of interest and could be a good candidate thanks its properties closed to hydrophobins (size and hydrophobicity). In conclusion, this methodology is developed to acquire a better knowledge about compounds produced by fungi at the surface of barley as well as to some industrial malt

Call number: LD2668 .T4 1961 F45

Thesis (PhD)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: A number of relevant brewing industry issues associated with malt quality were examined. These included beer foam quality, premature flocculation of yeast during fermentation and antimicrobial factors in malt. The cause of poor foam at a brewery relative to other similar breweries was identified as being related to the boiling temperature during wort preparation and the associated conformational changes of the abundant foam protein lipid transfer protein 1 (LTPl). The temperature range of 96 to 102°C was revealed to be critical. At the higher temperature the denaturation of LTP 1 was more extensive and its effectiveness as a foam protein was reduced. In addition, it was shown that the prominent role of LTPI with respect to foam was as a lipid binding protein, forming a lipid sink and protecting foam from lipid damage. The occurrence of malt associated premature yeast flocculation (PYF) during fermentation was induced in malt by the addition of extra-cellular fungal enzymes to the malt husk or by micro-malting barley in the presence of fungi. In addition, treating malt husk with commercial xylanase or adding commercial arabinoxylan to the fermentation also impacted on yeast flocculation. It was proposed that a range of molecular weight arabinoxylans formed by the enzymatic breakdown of the major barley husk component (arabinoxylan) resulted in PYF. Antimicrobial activity against brewing yeast (Saccharomyces cerevisiae), other fungi and bacteria was found in barley, malt and malt derived wort trub. Wort trub is the non-specific precipitate of protein, polyphenols and lipids formed during wort boiling and which is, to some extend, carried over in the wort to the fermentation. Antimicrobial activity appeared to increase during malting. The growth of brewery collected yeast was inhibited in the presence of brewery production wort when compared to the same wort filtered to remove the trub. Brewery yeast was found to be more sensitive to inhibition than laboratory propagated yeast of the same strain. Different strains of S. cerevisiae were also found to differ in their sensitivity to inhibition. Investigation revealed that the activity originated from the inside of the barley grain and impacted on yeast sugar uptake. However, there was no direct correlation detected between levels of antimicrobial activity in malt and fermentation performance. At high concentrations the factors were microcidal causing cell lysis. Partial characterisation of an antimicrobial extract from malt revealed the presence of a factor between 5 and 14 kDa, containing a cationic peptide component. The optimum pH stability was ±5 when it was also most cationic. The factor easily and irreversibly lost activity at extreme pH and when exposed to certain reagents but was heat resistant in accordance with its survival in wort trub. Preliminary results showed the presence of LTP1 associated with other peptides in the active cationic fraction from the one malt tested. The occurrence of malt related PYF and malt antimicrobial factors are associated with microbial contamination of the grain. The fungi generating the PYF factors from the barley husk while the barley's defence mechanism generates antimicrobial factors to cope with the pathogenic effect of the fungi. In addition there is a potential link between the foam protein LTP 1 and malt antimicrobial activity as LTP 1 or LTP 1 in association with another component(s) is potentially antimicrobial. / AFRIKAANSE OPSOMMING: 'n Aantal problematiese areas in die broubedryf, wat met mout geassosieer word, is ondersoek, naamlik bierskuimkwaliteit, voortydige flokkulering van gis tydens fermentasie en die invloed van antimikrobiese faktore in mout. Die oorsaak van swak bierskuim by 'n spesifieke brouery relatief tot ander soortgelyke brouerye was geidentifiseer as die moutekstrakkookpunt tydens moutekstrakbereiding. Tydens hierdie proses ondergaan dieskuimprotein, lipiedoordrag proteien 1 (lipid transfer protein 1, LTPI), 'n konformasieverandering. Die temperature tussen 96 to 102°C was kritiek t.o.v. ideale konformasieverandering vir skuimaktiwiteit. Denaturering van LTPI het by hoër temperature plaasgevind wat die skuimproteien se aktiwitiet verminder het. Daar is ook bewys dat LTPI 'n verdere rol in bierskuim speel aangesien dit 'n lipiedbindingsproteien is wat die skuimnegatiewe lipiede verwyder. Die voorkoms van moutgeassosieerde voortydige flokkulering van gis (PYF) tydens fermentasie is op twee maniere in mout geinduseer, naamlik: • deur die toevoeging van ekstrasellulêre swamensieme tot die moutdop • deur mikrovermouting van gars in die teenwoordigheid van swamme. Die behandeling van die moutdop met kommersiele xilanase of die toevoeging van kommersiele arabinoxilaan by fermentasies het ook die flokkulering van gis beinvloed. Die hipotese was dat PYF veroorsaak is deur 'n reeks arabinoxilane met verskillende molekulêre massas wat gevorm het tydens die ensimatiese afbraakproses van die primere moutdopkomponent (arabinoxilaan). Antimikrobiese aktiwiteit teenoor brouersgis (Saccharomyces cerevisiae), ander swamme en bakterie was teenwoordig in gars, mout en moutekstrakpresipitaat. Die presipitaat bestaan uit nie-spesifieke presipitate van proteien, polifenole en lipiede wat gedeeltelik in die gekookte moutekstrak agterbly. Daar is gevind dat antimikrobiese aktiwiteit tydens vermouting toe geneem het. Die groeiproses van brouersgis, gekollekteer by 'n brouery, was geinhibeer deur die teenwoordigheid van brouery-geproduseerde moutekstrak in vergelyking met dieselfde moutekstrak wat gefiltreer was om die presipitaat te verwyder. Die brouersgis was meer sensitief heens inhibisie in vergeleke met dieselfde gisstam wat opgegroei is in die laboratorium. Verskillende S. cerevisiae stamme het ook verskille in sensitiwiteit getoon t.o.v. the antimikrobiese komponente in die moutekstrakte. 'n Verdere ondersoek het getoon dat die oorprong van die inhiberende aktiwiteit die interne dele van die gars is, asook dat dit die gissuikeropname beinvloed. Daar was egter geen direkte verband tussen antimikrobiese aktiwiteit in mout en fermentasie effektiwiteit, soos gemeet onder laboratorium toestande, nie. Hoë konsentrasies van die faktore het egter gelei tot seldood weens sellise. 'n Kationiese peptiedbevattende fraksie tussen 5 en 14 kDa en 'n optimale pH stabliliteit van 5 is gevind deur gedeeltelike karakterisering van 'n antimikrobiese moutekstrak. Die aktiewe fraksie se aktiwiteit is onomkeerbaar vernietig by ekstreme pH en blootstelling aan sekere reagense. Die aktiewe verbinding(s) is egter hittebestand en resultate het getoon dat hierdie aktiwiteit die brouproses oorleef as deel van die moutektrakpresipitaat. Voorlopige resultate van die een mout wat getoets is het die teenwoordigheid van LTP 1 getoon, asook die moontlike assosiasie met ander peptiede of kleiner komponente in die aktiewe kationiese fraksie. Die voorkoms van moutgeassosieerde PYF en antimikrobiese faktore in mout word met die mikrobiologiese kontaminasie van gars verbind. Swamme produseer die PYF faktore vanuit die moutdopkomponente, terwyl die plant weer antimikrobiese faktore produseer as deel van 'n beskermingsmeganisme teen die patogene effek van die swamme. Daar is ook 'n potensieele verwantskap tussen bierskuimproteien LTP 1 en antimikrobiese faktore in mout, aangesien LTPI ofLTPl tesame met 'n ander verbinding(s) moontlik antimikrobies is.

Die primären genetischen Veränderungen gastraler MALT-Lymphome zeigen verschiedene Pathogenesen auf. In 20 bis 30 Prozent der DLBCL kann eine Translokation t(14;18)(q32;q21) nachgewiesen werden, bei der das antiapoptotisch wirkende Bcl-2-Gen transloziert wird. Dies führt zu einer Überexpression von Bcl-2. Die Translokation t(11;18)(q21;q21) wurde in bis zu 50 Prozent der MZBZL vom MALT-Typ und wenigen DLBZL nachgewiesen. Dabei werden unterschiedlich lange Teile des MALT1-Gens in BIRC3 (ehemals: Apoptose- Inhibitor- Gen API2) auf 11q21 integriert. Mit den Translokationen scheint man bei einem Teil der gastrointestinalen Lymphome die primäre genetische Veränderung entdeckt zu haben. Bei Lymphomen, bei denen die Pathogenese nicht durch Translokationen vorangetrieben wird, könnten die gleichen, von Translokationen betroffen Gene durch Amplifikationen/ Mutationen überexprimiert/ aktiviert werden. Im Rahmen dieser Doktorarbeit wurden die Gene MALT1 und Bcl-2 hinsichtlich Amplifikationen der genomischen DNA untersucht. Amplifikationen des Bcl-2-Gens konnten kürzlich bei einigen t(14;18)(q32;q21)-negativen DLBCL und follikulären Lymphomen nachgewiesen und auch im Rahmen dieser Doktorarbeit gezeigt werden. Mittels semiquantitativer PCR konnte in vier von 30 untersuchten DLBCL-Fällen (13,3 Prozent) eine Amplifikation des Bcl-2-Gens nachgewiesen werden. Die Hypothese, dass Bcl-2-Amplifikation mit folgender Überexpression des Bcl-2-Proteins (neben Bcl-2-Translokation) eine wichtige Rolle in der Pathogenese bei DLBCL spielt, wird mit diesen Ergebnissen gestützt. Zudem zeigten zwei von 14 MZBZL-Fällen (14,3 Prozent) eine Bcl-2-Amplifikation. Hieraus ergibt sich die Vermutung, dass Bcl-2 auch eine wichtige Rolle bei der Entstehung der MZBZL vom MALT-Typ spielen könnte. Bisher konnten Bcl-2-Gen-Beteiligungen (zum Beispiel t(14;18)(q32;q21)) nicht nachgewiesen werden. Amplifikationen des MALT1-Gens wurden kürzlich als mögliche primäre Ursache für die Entstehung von Lymphomen beschrieben. In vier der 30 untersuchten DLBCL-Fällen (13,3 Prozent) und einem t(11;18)(q21;q21)-negativem MZBZL-Fall konnten mittels semiquantitativer PCR Amplifikationen von MALT1 detektiert werden. Die Ergebnisse zeigen, dass MALT1 als dominantes Onkogen in der Pathogenese von gastralen MZBZL vom MALT-Typ und primär gastralen DLBCL zu agieren scheint. Es kann sowohl durch Translokationen, wie auch durch genomische Amplifikationen dysreguliert werden. / The translocation t(14;18)(q32;q21), which is present in 20 bis 30 percent of DLBCL (diffuse-large-B-cell-lymphoma) leads to overexpression of Bcl-2. The translocation t(11;18)(q21;q21) can be detected in up to 50 percent of MZBCL (marginal zone B-cell lymphoma) of MALT-typ and a low number of DLBCL. Thereby parts of the MALT1-gene get integrated in BIRC3. The dissertation shows, that in gastric MALT-lymphomas not only translocation, but also amplifications of the MALT1- and Bcl-2-gene might play an important part in the development of these lymphomas. In 13,3 percent of DLBCL and 14,3 percent of MZBCL an amplification of the Bcl-2-gene, which may lead to overexpression could be demonstrated. An amplification of the Bcl-2-gene in MZBCL of MALT-typ has not been verified before. In 13,3 percent of DLBCL and 1 t(11;18)(q21;21)-negativ case of the analysed MZBCL an amplification of the MALT1-gene could be attested. This leads to supposition that MALT1 acts as an dominant oncogene in the development of gastric MZBCL of MALT-typ and primary gastric DLBCL.