Prediction of potential malt extract and beer filterability using conventional and novel malt assays

Abstract

Colourimetric assays were used to measure the activities of six key hydrolases endogenous to barley: β‐glucanase, xylanase, cellulase, α‐amylase, beta‐amylase and limit dextrinase. The analysed barley malt samples were previously characterised by 27 conventional malt quality descriptors. Correlations between enzymatic activities and brewing parameters such as extract yield, fermentability, viscosity and filterability were investigated. A single extraction protocol for all six hydrolases was optimised and used for multi‐enzyme analysis using fully automatable assay formats. A regression analysis between malt parameters was undertaken to produce a relationship matrix linking enzyme activities and conventional malt quality descriptors. This regression analysis was used to inform a multi‐linear regression approach to create predictive models for extract yield, apparent attenuation limit, viscosity and filterability using the Small‐scale Wort rapId Filtration Test (SWIFT) and two different mashing protocols – Congress and a modified infusion mash at 65°C (MIM 65°C). It was observed that malt enzyme activities displayed significant correlations with the analysed brewing parameters. Both starch hydrolases and cell wall hydrolase activities together with modification parameters (i.e. Kolbach index) were found to be highly correlated with extract yield and apparent attenuation limit. Interestingly, it was observed that xylanase activity in malts was an important predictor for wort viscosity and filterability. It is envisaged that the automatable measurement of enzyme activity could find use in plant breeding progeny selection and for routine assessment of the functional brewing performance of malt batches. This analytical approach would also contribute to brewing process consistency, product quality and reduced processing times. © 2019 The Institute of Brewing & Distilling

Impact of exogenous α-amylases on sugar formation in straight dough wheat bread

“…Extraction of α-amylase was performed according to Cornaggia et al [27]. The amylase preparations or bread (1.0 g dry matter) were extracted each with 10 mL extraction buffer (0.1 mol/L sodium maleate, pH 5.5, 1.0 mg/mL bovine serum albumin, 0.025 mol/L DTT) for 16 h at 22 °C.…”

Analysis of Physicochemical Parameters of Congress Worts Prepared from Special Legume Seed Malts, Acquired with and without Use of Enzyme Preparations

“…Beer with the addition of unmalted wheat and corn grist, produced and analysed by Vinko Krstanović et al, resulted in wort of pH higher (5.73) than most of the legume seed malt worts [ 32 ]. Wort pH is, usually, in the traditional congress mash analysis, a useful predictor for the extract of the acquired wort, as lower pH is known to improve saccharification, extract content, as well as filtering time [ 33 ]. However, as was said earlier, there is no available research concerning optimal pH values for activity of enzymes present in the legume seed malts.…”

Determination of Cytolytic Malt Modification – Part II: Impact on Wort Separation

“…Since the 1970s, different studies have investigated the impact of different mashing procedures on wort composition to estimate the processability of different barley varieties. [30][31][32][33][34] Over the years, however, the variety characteristics have changed due to the breeding process, requiring adapted extraction procedures. In consequence, there exist several extraction procedures, which are difficult to compare due to different processes and features despite a large amount of data available.…”