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Vereecken E.,Catholic University of Leuven | Vanoirbeek K.,Center for Food and Microbial Technology | Roels S.,Catholic University of Leuven
Energy Procedia | Year: 2015

This paper presents a preliminary study on the validity of the mould prediction models frequently applied in the building physics field (VTT model, Sedlbauer's isopleths, biohygrothermal model), and this based on laboratory results found in the literature. Although similar laboratory experiments serve as the input for the development of the prediction models, quite large discrepancies are observed. These findings can be used when, for instance, upgrading the current mould prediction models. Apart from a correct conversion of measurements into the mould prediction models, the collection of reliable data sets is of course of seminal importance. Therefore, additionally, some potential difficulties, challenges, etc. in experimental mould growth research will be put forward. © 2015 The Authors.

Steensels J.,Laboratory for Systems Biology | Daenen L.,Anheuser Busch InBev Inc. | Malcorps P.,Anheuser Busch InBev Inc. | Derdelinckx G.,Center for Food and Microbial Technology | And 2 more authors.
International Journal of Food Microbiology | Year: 2015

Ever since the introduction of controlled fermentation processes, alcoholic fermentations and Saccharomyces cerevisiae starter cultures proved to be a match made in heaven. The ability of S. cerevisiae to produce and withstand high ethanol concentrations, its pleasant flavour profile and the absence of health-threatening toxin production are only a few of the features that make it the ideal alcoholic fermentation organism. However, in certain conditions or for certain specific fermentation processes, the physiological boundaries of this species limit its applicability. Therefore, there is currently a strong interest in non-. Saccharomyces (or non-conventional) yeasts with peculiar features able to replace or accompany S. cerevisiae in specific industrial fermentations. Brettanomyces (teleomorph: Dekkera), with Brettanomyces bruxellensis as the most commonly encountered representative, is such a yeast. Whilst currently mainly considered a spoilage organism responsible for off-flavour production in wine, cider or dairy products, an increasing number of authors report that in some cases, these yeasts can add beneficial (or at least interesting) aromas that increase the flavour complexity of fermented beverages, such as specialty beers. Moreover, its intriguing physiology, with its exceptional stress tolerance and peculiar carbon- and nitrogen metabolism, holds great potential for the production of bioethanol in continuous fermentors. This review summarizes the most notable metabolic features of Brettanomyces, briefly highlights recent insights in its genetic and genomic characteristics and discusses its applications in industrial fermentation processes, such as the production of beer, wine and bioethanol. © 2015 Published by Elsevier B.V.

Khalesi M.,Center for Food and Microbial Technology | Venken T.,University of Manchester | Deckers S.,Center for Food and Microbial Technology | Winterburn J.,Catholic University of Leuven | And 6 more authors.
Industrial Crops and Products | Year: 2013

Due to the exceptional properties and many potential applications of hydrophobins, special fungal proteins, it becomes necessary to develop a real scale procedure for their production and purification. In our previous study (Deckers et al., 2010) [CO 2-hydrophobin structures acting as nanobombs in beer, Brew. Sci. 63:54-61], the strong interaction of CO 2-hydrophobin was demonstrated. For the first time, in an approach to isolate hydrophobin HFBII from the growth media of Trichoderma reesei, a foam fractionation system using CO 2 as the sparging gas was investigated in this study. Using CO 2 foam fractionation, the concentration of HFBII was increased from 0.10±0.02mg/mL up to 0.57±0.04mg/mL. This was shown after a purification step by conventional liquid chromatography and identification of the goal protein using MALDI-TOF. The obtained molecular weight of the protein was 7.042kDa which corresponds to the complete molecule of HFBII, minus the last aminoacid. Micro-spectrophotometry was used for quantification of purified HFBII. Moreover, different parameters of the foam fractionation system were optimized. The concentration of the protein after treatment by CO 2 followed by liquid chromatography was increased from 0.32±0.02 to 0.44±0.06mg/mL when the flow rate of gas injection was changed in the range of 1-3L/min. The highest amount of HFBII equal to 0.57±0.04mg/mL was obtained by the highest ratio of liquid height over the column height. Using the larger pore size frits causes increased protein absorption as well. The gushing potential of samples revealed that in contrast to the samples before CO 2 treatment, interestingly, no gushing was observed for the samples after treatment. The possibility that stable aggregates of HFBII molecules are formed as a consequence of their high concentration is discussed in this paper. By using DLS analysis of the overfoam, 100nm particle size of CO 2 nanobubbles coated by HFBII was obtained. The final concentration of the protein was carried out using Amicon ® ultracentrifuge device with the average recovery of 63.8±8.2%. © 2012 Elsevier B.V.

De Maere H.,Research Group for Technology and Quality of Animal Products | De Maere H.,ISA Group | Fraeye I.,Research Group for Technology and Quality of Animal Products | De Mey E.,Research Group for Technology and Quality of Animal Products | And 4 more authors.
Meat Science | Year: 2016

This study investigates the potential of producing red coloured dry fermented sausages without the addition of nitrite and/or nitrate. Therefore, the formation of zinc protoporphyrin IX (Zn(II)PPIX) as naturally occurring pigment, and the interrelated protoporphyrin IX (PPIX) and heme content were evaluated during nitrite-free dry fermented sausage production at different pH conditions. Zn(II)PPIX was only able to form in dry fermented sausages at pH conditions higher than approximately 4.9. Additionally, the presence of Zn(II)PPIX increased drastically at the later phase of the production process (up to day 177), confirming that in addition to pH, time is also a crucial factor for its formation. Similarly, PPIX also accumulated in the meat products at increased pH conditions and production times. In contrast, a breakdown of heme was observed. This breakdown was more gradual and independent of pH and showed no clear relationship with the formed amounts of Zn(II)PPIX and PPIX. A statistically significant relationship between Zn(II)PPIX formation and product redness was established. © 2015 Elsevier Ltd.

Postulkova M.,Institute of Chemical Technology Prague | Postulkova M.,Czech Institute of Chemical Process Fundamentals | Riveros-Galan D.,Center for Food and Microbial Technology | Cordova-Agiular K.,Center for Food and Microbial Technology | And 6 more authors.
Trends in Food Science and Technology | Year: 2016

Background: Beer gushing is an uncontrolled escape of wet foam when opening a beer bottle, which is not caused by high temperature or shaking. Primary gushing is associated with fungal contamination of barley but the main role in gushing is played by carbon dioxide and surface active proteins called hydrophobins produced by fungi. Secondary gushing is understood as the effect of non-hydrophobin related factors, which either provoke gushing independently and/or can support the expression/intensity of primary gushing. So far there, there is no fully functional gushing suppression strategy at industrial scale. Scope and approach: This review article aims to clarify the underlying mechanism of primary gushing and simultaneously provide an overview of knowledge concerning different strategies of suppressing primary gushing. The published methods of reducing and suppressing primary gushing were analyzed and structured according to various technological sections of beer production. Emphasis was placed on the aspects of applicability in industrial practice. Key findings and conclusions: By analyzing the available data, the following strategies of reducing the risk of beer gushing were identified as the most promising (i) germination of barley in the presence of micro-organisms inhibiting the hydrophobin producing fungi, (ii) use of hop oil and products with antigushing effect, and (iii) coating of the glass bottle necks with hydrophobin binding layers. This study intends to inspire research and promote application of new approaches to control gushing. © 2016 Elsevier Ltd.

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