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1 Technische Universität München, Lehrstuhl für Brau- und Getränketechnologie, Freising, Germany The development of a kinetic modeling of the formation of 2- and 3-MB is a useful tool to estimate the wort flavor during the wort boiling and the flavor stability of beer. A model experiment was performed, using D-glucose/D-maltose and L-leucin/isoleucin to study Maillard reaction in a buffer solution of a pH value of 5.2. The development of this kinetic model was based on the correlation between the concentrations of 2-, 3-MB and the concentration of L-leucin/isoleucin. According to a statistical analysis, there is no significant difference in changes on concentration of D-Glucose/D-Maltose. In order to understand the reaction mechanism better, a multi response kinetic model was used. Using the software Athena Visual Studio TM , the reaction rates of the main reaction step of the Maillard reaction and the activation energy were calculated respectively. The developed kinetic model gives a good fit with the experimental data. P49 Origin of the flavour active aldehydes cis- and trans-4,5-Epoxy-2E-decenal Konrad Neumann 1 , Leif A. Garbe 1 1 VLB Berlin / TU Berlin, Berlin, Germany Flavor active cis- and trans-4,5-epoxy-2E-decenal isomers are important (off)-flavor compounds in foods. Trans-4,5-epoxy-2E-decenal has a very intensive metallic taste and smell with very low thresholds. In the literature, the aroma of cis-4,5-epoxy-2E-decenal is described as citrus-like, sweet, fatty and malty. Even the concentrations of epoxydecenales are comparably low, epoxydecenal isomers were identified as key odorants of food products. In fresh beer we analyzed epoxydecenal concentrations with 20pg/L. As their origin, degradation of linoleic acid is proposed but not yet verified. To prove origination, we added stable isotope labeled linoleic acid to beer. In a second set-up we used 18 O in the head space of the beer bottles. By previously described workup procedures, and the usage of GC-MS-Methods we could trace the isotope labels appearing in the degradation products of linoleic acid and so elucidate the origin of both isomers of epoxy-2E-decenal. P50 Polyfunctional thiols in aged beer: Focus on the ribes off- flavour Thi Thu Hang Tran 1 , Jacques Gros 1 , Sonia Collin 1 1 Université catholique de Louvain, Unité de brasserie et des industries alimentaires, Earth and Life Institute ELIM, Louvain-la-Neuve, Belgium For brewers, the term “ribes” refers to a characteristic taint encountered in some aged beers submitted to oxidation. A very strong odorant thiol, 3-sulfanyl-3-methylbutyl formate (3S3MB-F) was here identified as responsible for this blackcurrant/catty note. The sensorial threshold of 3S3MB-F was much lower (57 ng/L in beer) than that measured for its acetate analog. Thiol selective pHMB extraction was applied to a large number of commercial and pilot beers (lager and top-fermented beers). The extracts were analysed by GC-O/PFPD/MS. Up to 629 ng/L of 3S3MB-F were detected in commercial lager beers after 1 month of natural ageing. The highest concentrations (1230 ng/L) were found in top-fermented beers with higher oxygen at bottling. Accelerated ageing on model media confirmed the key role of oxygen.
P51 Release of hop flavours from cysteine conjugates by apotryptophanase Sonia Collin 1 , Jacques Gros 1 , Thi Thu Hang Tran 1 1 ELI - M (Applied Microbiology) / Université catholique de Louvain, Laboratoire de brasserie et des industries alimentaires (INBR), Louvain-la-Neuve, Belgium Polyfunctional thiols are contributors to the hop varietal aroma of beer. Besides free thiols, cysteine-Sconjugates have been evidenced as additional components of the thiol potential of hop. Such cysteine adducts are investigated here in 8 hop cultivars (Amarillo, Cascade, Citra, Mosaic, Nelson Sauvin, Saaz, Simcoe, Tomahawk) and in different hop forms. Hop hydroalcoholic extracts were purified on a cation exchanger and subjected to apotryptophanase beta-lyase activity. Several thiols were released by the enzymatic treatment, including the skunky-like 3-methyl-2-buten-1-thiol, the box-tree-like 4- sulfanyl-4-methylpentan-2-one, and the grapefruit-like 3-sulfanylhexan-1-ol. Mosaic and Cascade hop varieties exhibited the highest bound 4-sulfanyl-4-methylpentan-2-one and 3-sulfanylhexan-1-ol potentials, respectivelly, while the Amarillo and Tomahawk cultivars were confirmed to be important source of skunky-like thiols. Surprisingly, hop CO 2 extracts proved to contain cysteine conjugates. P52 Odorant phenolic markers in chocolate malts. Fate of them through beer ageing Caroline Scholtes 1 , Sonia Collin 1 1 Université catholique de Louvain, ELIM - Laboratoire de brasserie et des industries alimentaires, Louvain-la-Neuve, Belgium Issued from enzymatic or thermic decarboxylation of phenolic acids, volatile phenols are responsible of typical spicy notes in a large range of beverages. Among these, brown special beers, exhaling strong coffee aromas, generally contain dark specialty malts, produced at higher kilning temperatures than typical pilsen malts and through specific equipment like roasting drum or torrefactor. A panel of malts (4,5 to 1500 EBC) were analysed and the resulting phenol-specific extracts investigated by gas chromatography - olfactometry (GC-O/AEDA) and mass spectrometry (GC-MS). Different profiles emerged from this study, according to the temperature-duration conditions applied. Interesting markers were highlighted in torrefied/chocolate malts and derived beers such as guaiacol. Moreover, investigation of aged beers revealed and unexpected hidden potential of guaiacol and analogs, progressively liberated through storage by acid hydrolysis. P53 Sake fermentations: what can brewers learn Daniel Kerruish 1 , Trevor Phister 1 , Katherine Smart 2 1 University of Nottingham, Nottingham, United Kingdom, 2 SABMiller plc, Woking, United Kingdom Sake fermentations use rice, water and a co-culture of Aspergillus oryzae (Koji) and Saccharomyces cerevisiae (Kyokai) to achieve ethanol yields of up to 22%. Sake fermentations derive fermentable sugars from the breakdown of polished rice by the exogenous enzymes produced by Aspergillus oryzae. These fermentable sugars are then utilised by S. cerevisiae. Sake fermentations are therefore complex in nature and poorly understood. The purpose of this work is to understand the reasons why Sake yeast are apparently so ethanol yielding and ethanol tolerant. There are several possible reasons for this: fermentations are conducted with Aspergillus oryzae this mixed fermentation may be beneficial to the yeast; Sake yeast strains may also have a more effective ethanol defence. In this presentation these two hypotheses will be discussed.
Page 1 and 2: Poster P1 Soluble dietary fiber as
Page 3 and 4: P6 Predicting the flavor stability
Page 5 and 6: Protein-thiols in beer and througho
Page 7 and 8: 1 Lodz University of Technology, In
Page 9 and 10: avoided and the draught beer qualit
Page 11 and 12: P26 DMTS reduction through control
Page 13 and 14: Toru Kishimoto 1 , Kazuhiko Uemura
Page 15 and 16: at different stages along the brewi
Page 17 and 18: sources, to account for biological
Page 19: eer fermentation. We thank FCT for
Page 23 and 24: Unmalted adjuncts are used in brewi
Page 25 and 26: details and the relevance to manufa
Page 27 and 28: was used to evaluate the predictive
Page 29 and 30: P74 Critical view on the calculatio
Page 31 and 32: P78 The "trickle-down effect" in fl
Page 33 and 34: P83 Making gluten-free beers with b
Page 35 and 36: Innovative technologies like next g
Page 37 and 38: predictions correlated well with of
Page 39 and 40: P99 Brewery carbon footprint: A cas
Page 41 and 42: Enriqueta Martinez-Rojas 1 , Renate

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