39 research outputs found
Preliminary evaluation of durum wheat (Triticum Turgidum Subsp Durum) during malting process
No full textDurum (T. turgidum subsp. durum) wheat production worldwide is substantially less than that of common wheat (Triticum aestivum) mainly due to the relatively limited end-users. In order to evaluate malting and brewing suitability, sixteen old durum wheat landraces were malted at micro scale. Results show malt quality parameters in the range 78.2–85.9% for the extract, 72.9–80.9% for the fermentability, 3–5 EBC units for the colour, 0.49–0.79% dm for water-extractable arabinoxylans and 0.043–0.059% dm for the β-glucans. Regarding wort viscosity (1.53–1.92 mPa s), we found negative correlation with endo-1,4-β-D-xylanase, positive correlation with endo-β-glucanases and soluble proteins, while no correlations were found with arabinoxylan and betaglucan wort content. These results showed that some durum wheats, such as Trentino, Martinella, Gioia, Inglesa, Francesa, Giustalisa and Bidì have suitable characteristics for malting and brewing. The improvement of the malting process is required for the other durum wheats
Screening of durum wheat landraces (Triticum turgidum subsp. durum) for the malting suitability
No full textDurum (T. turgidum subsp. durum) wheat production worldwide is substantially less than that of common wheat (Triticum aestivum) mainly due to the relatively limited end-users. In order to evaluate malting and brewing suitability, sixteen old durum wheat landraces were malted at micro scale. Results show malt quality parameters in the range 78.2–85.9% for the extract, 72.9–80.9% for the fermentability, 3–5 EBC units for the colour, 0.49–0.79% dm for water-extractable arabinoxylans and 0.043–0.059% dm for the β-glucans. Regarding wort viscosity (1.53–1.92 mPa s), we found negative correlation with endo-1,4-β-D-xylanase, positive correlation with endo-β-glucanases and soluble proteins, while no correlations were found with arabinoxylan and betaglucan wort content. These results showed that some durum wheats, such as Trentino, Martinella, Gioia, Inglesa, Francesa, Giustalisa and Bidì have suitable characteristics for malting and brewing. The improvement of the malting process is required for the other durum wheats
Humulus Lupulus: Hop Alpha-acids Isomerization. A Review.
No full textThis paper gives an extensive overview of the research performed in relation to hop a-acids isomerization. The objective is to present a summary on developments and findings which can serve as a background for future work regarding more efficient use of humulones and isohumulones. To this end, first, an overview of the research which has been performed in relation to the a-acids isomerization mechanism and kinetics is provided. Following, the influence of common parameters, such as temperature, pH, the concentration of humulones, metal ion catalysts, etc., on a-acids isomerization is presented. In this review, structures and mechanisms that are presented correspond to original data found in literature and were, consequently, not adapted to the newly proposed structure of a-acids and iso-a-acids (According to Urban et al. [1]).status: Publishe
Including experimental uncertainty on the independent variables when modelling microbial dynamics: The combined effect of pH and acetic acid on the growth rate of E. coli K12
No full textModelling methods applied in predictive microbiology generally neglect the importance of uncertainty on the measurement of the independent variables. The Ordinary Least Squares (OLS) method that is commonly applied in predictive microbiology is only applicable if the experimental error on the inputs of the model are insignificant. However, this does not apply for many types of experimental measurements of the independent variables. Therefore, a parameter estimation method was adapted in this research for the estimation of the parameters of secondary models, taking into account uncertainty on the measurement of the influencing food characteristics. This parameter estimation method was based on the work of Stortelder (1996) and is referred to as the Weighted Total Least Squares method (WTLS). The method is formulised as an extension of the commonly used OLS method. Consequently the current WTLS method (i) is easily implemented using similar numerical methods, (ii) reduces to an OLS method when the measurement error on the model inputs is negligible and (iii) enables the evaluation of the accuracy of the model parameter estimates based on the same approximations.sponsorship: This work was supported by project PFV/10/002 (Center of Excellence OPTEC-Optimization in Engineering) of the KU Leuven Research Council, projects G093013N and KAN 1518913N of the Fund for Scientific Research-Flanders, and the Belgian Program on Interuniversity Poles of Attraction, initiated by the Belgian Federal Science Policy Office. (Fund for Scientific Research-Flanders|G093013N, Fund for Scientific Research-Flanders|KAN 1518913N, Belgian Program on Interuniversity Poles of Attraction, KU Leuven Research Council|PFV/10/002)status: Publishe
On the contribution of malt quality and the malting process to the formation of beer staling aldehydes: a review
Get PDFDespite decades of extensive research, beer flavour instability remains a challenge for both brewing and malting industries. Malt impacts the brewing process as well as the quality of the final beer. It also affects the stability of beer flavour, as it delivers to the brewing process various compounds with the potential to compromise the desired flavour characteristics of beer. These include staling aldehydes and their precursors, such as amino acids, reducing sugars, α-dicarbonyls and bound-state aldehydes. In general, the content of these compounds depends on barley variety and quality, the malting regime and final malt quality. Malt that represents a low potential for beer staling, i.e. that has low values of Kolbach Index, heat load, colour, LOX activity, Strecker aldehydes, transition metal ions and high antioxidative activity, leads to beer with enhanced flavour stability. However, the consistent production of malt with the desired quality remains challenging. Approaches to achieve this include adjustment of steeping and germination conditions, allowing control of grain modification and thus, the reservoir of aldehydes precursors. Also, the application of alternative kilning technologies may reduce the applied heat load, responsible for the formation of staling aldehydes and triggering development of the oxidising free radical species. This review provides an evaluation of current knowledge on the contribution of the malting process and malt quality to the formation of beer staling aldehydes. © 2021 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling
The Use of Hop Polyphenols during Brewing to Improve Flavor Quality and Stability of Pilsner Beer
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Hop and hoppy aroma : comprehensive characterization of hop essential oils and hoppy aroma of beer
No full textThe impact of wort production on the flavour quality and stability of pale lager beer
No full textFine milling in combination with thinbed mash filters has been introduced into the brewing industry more than 20 years ago. Although clearest worts can be obtained at highest gravity, in combination with high extract yield and improved starch conversion, a majority of brewers still use the conventional coarse milling in combination with lautertuns. Brewers seem still afraid having a negative impact of fine milling on wort and beer quality especially with regard to over extraction of polyphenols, proteins and oxidative enzymes. A lack of detailed data comparing both wort production methods could be a reason. In this study, the faster wort filtration as well as higher extract yield has been confirmed when using fine milling and a thin bed filter. A higher concentration of fermentable sugar led to this increased yield and not an increased level of proteins and polyphenols. On the contrary, fine milling in combination with thicker mash and thin bed filtration results in a lower level of haze sensitive protein in the pitching wort in comparison to coarse grist and the use of a lautertun. No striking differences have been found comparing analyses of fresh beer. Also during forced ageing of the beers at 30 °C, no difference in the formation of flavour negative compounds or degradation of bitterness has been noticed. Both wort production methods result in highly comparable beers with equal flavour stability.status: Publishe
