Relationship between Kolbach index and other quality parameters of wheat malt

Maiorca wheat malt: A comprehensive analysis of physicochemical properties, volatile compounds, and sensory evaluation in brewing process and final product quality

This study explores the potential of Maiorca wheat malt as an alternative ingredient in beer production, investigating its impact on the brewing process and beer quality at different recipe contents (50 %, 75 %, 100 %). The study encompasses a comprehensive analysis of key malt parameters, revealing Maiorca malt's positive influence on maltose, glucose, filterability, extract, free amino nitrogen, and fermentability. Notably, the malt exhibited heightened levels of α-amylase and β-amylase enzymes compared to conventional commercial malt. Furthermore, the analysis of aroma compounds and subsequent sensory evaluations unveiled a significant correlation between the proportion of Maiorca malt in the formulation and intensified estery, fruity, malty, honey, complemented by a reduction in attributes such as aromatic compounds, phenolic, yeasty, sulfury, oxidized, and solvent-like odors. This research underscores the favorable contribution of Maiorca wheat malt to enhancing both the brewing process and final beer quality, highlighting its potential as an innovative ingredient in brewing practices.

The effect of barley to wheat ratio in malt blends on protein composition and physicochemical characteristics of wort and beer

The present work explored the effect of barley to wheat ratio in malt blends on protein composition and physicochemical characteristics of wort and beer. Results illustrated that the addition of wheat malt can significantly improve the soluble protein of wort and the final beer, and it can provide more > 2.2 kDa protein in final beer, which is mainly derived from the raw wheat malt, but also including some protein produced in the fermentation process, such as some protein between 29 and 66.4 kDa. Though the content of > 15 kDa protein was relatively lower than the protein whose molecular weight was < 15 kDa, but it had important effects on total nitrogen, total water-soluble protein, free amino nitrogen, chromaticity, and viscosity of final beer. The addition of wheat malt significantly improved the concentration of 2.2-15 and > 15 kDa protein, but higher percentage of addition ratio can decrease the foam stability of the beer. PRACTICAL APPLICATION: This findings can reasonably control the protein content and types of wheat beer, improve the quality of wheat beer, solve the key technological problems, and expand and popularize the application of wheat in beer industry.

Effect of malting process duration on malting losses and quality of wheat malts

The study assesses impact of malting process duration on malting losses and quality of malts obtained from three varieties of winter wheat, i.e., Elixer, Rockefeller and Gimantis. The findings show that increased duration of the malting process (from 4 to 7 days) corresponded to greater total weight loss, with the most significant differences observed between 5-day and 6-day wheat malts. The qualitative analysis of the malts was carried out in accordance with EBC methodology. The assessments showed that the 5-day long malting process applied to the relevant wheat varieties resulted in production of high-quality malt with optimum malting losses observed in the case of Elixer and Rockefeller varieties. Slightly higher malting losses were identified in the case of Gimantis, and the malt obtained from this variety had very high contents of soluble protein (on average 5.34% d.m.) and Kolbach Index (average of 50.49%), which reflects high proteolytic activity during the grain malting process and a need to modify the malting process for this variety.

Relationship between the index of protein modification (Kolbach index) and degradation of macromolecules in wheat malt

Kolbach index (KI) is an important index to evaluate the qualities of malt, which will affect protein molecular composition, enzyme activity, and other macromolecules degradation during wheat malting. In this paper, the relationship between wheat (Triticum aestivum L.) malts KI and the (i) characterization of albumins, globulins, gliadins, and glutenins and their hydrolysis and (ii) the enzymatic breakdown of starch and arabinoxylans during malting were studied. As malt KI values increased, all fractions of glutenins and gliadins were extensively hydrolyzed. The higher Mw globulins (36.6 to 70.8 kDa) were also increasingly degraded at higher KI values, but the concentration of smaller globulin fractions (14.9 to 35.0 kDa) had increased significantly. As for albumins, although their overall concentration had increased as KI increased, changes in the concentration of individual albumin fractions was more complex. While there were significant increases in the concentration of some new albumin proteins (43.8 and 84.4 kDa), the concentration of some albumins decreased (21.1 to 64.3 kDa), and some fractions had completely disappeared (28.8 and 64.3 kDa). Following mashing, the hydrophobicity of the worts had decreased significantly at higher KI values. At malt KI values between 39.5% and 42.7%, the enzymatic activity was at its highest, the degradation of starch was adequate and stable, and the concentration of water-soluble arabinoxylans was optimal. A KI value of about 39.5% to 42.7% was therefore considered optimal for the production of wheat malts with superior quality attributes. PRACTICAL APPLICATION: The findings from this study will be valuable to beer companies; a more precise control of the malting and brewing parameters, fundamental for the production of high-quality wheat malts and wheat beer, can be achieved.

Research of Malting Procedures for Winter Hard Wheat Varieties-Part II

This paper examines the influence of malting process parameters on the wheat malt quality obtained from the assortment of winter red wheat. For this assortment, previous research established that strongly restrictive and strongly intensive malting processes are not suitable, that is, they do not significantly improve the quality of the obtained wheat malts, and in some segments, they even disturb it. Therefore, modifications were introduced to both procedures, and malting was performed with moderately intensive procedure D and moderately restrictive procedure E. Starting wheat, indicators of micromalting process success, and finished wheat malts were analyzed. The results showed that the moderately restrictive malting process (E) significantly improves not only the values for soluble N for almost all tested varieties, but also the values of cytolytic degradation success (wort viscosity, filtration time), and extract yield. The moderately intensive procedure did not improve the determined indicators; for many varieties, the modification even resulted in poorer values. Furthermore, the moderately restrictive procedure allows a strong individual response of a particular variety to the process conditions during malting, which is very important for the assessment of the malting potential for a particular variety. Namely, when assessing the actual malting quality of an individual variety, it is necessary to include amylolytic indicators and indicators of enzymatic strength. In this way, a group of varieties were established which had an increased initial share of total N (varieties no. 7, 8, 9, 10, 12, 13, and 16). These varieties, by this procedure, gave the best quality wheat malts in the entire examined assortment.

Research of Malting Procedures for Winter Hard Wheat Varieties-Part I

This paper examines the influence of the malting process of red hard wheat varieties (which have many characteristics of soft wheat varieties and represent a transitional form between durum and soft wheat). According to the values of total and soluble proteins and viscosity of wort these wheat varieties belong to the second malting quality group. To establish the individual response of each variety and estimate how the chosen varieties respond in groups to different process conditions, sixteen varieties were selected and malted according to the standard procedure (A), restrictive procedure (B), and intense procedure (C). Starting wheat, indicators of micromalting process success, and finished malts were analyzed. It was found that the restrictive procedure (B) gives poor results for the values of proteolysis performance parameters (soluble N, free amino nitrogen (FAN)) with simultaneous disturbance and values of cytolytic degradation (viscosity and filtration time) and extract yield. At the same time, this procedure lacks a stronger individual response of an individual variety to the process conditions during malting (F/C difference and extract yield). The optimal malting process for the specified assortment would include the modification of processes B and C in a way to alleviate the restrictive conditions in process B, or in a way to reduce the intensity of the decomposition in process C.

Technological Assessment of Winter Cultivar of Common Wheat (Triticum aestivum L.) and Winter Barley (Hordeum vulgare L.) for Pale Malt Production

The study was designed to assess technological quality of grains from two wheat cultivars (Elixer and Rockefeller), as well as one cultivar of winter (Joy) and one cultivar of spring barley (Irina), and to carry out the malting process at temperature of 15°C for 5 days. Malt analyses were carried out in accordance with the ECB Methods. The wheat malts were found with lower Kolbach index, and high viscosity was identified in wort obtained from wheat. The findings related to the wheat malts showed better quality parameters in Elixer variety compared to Rockefeller variety. Elixer wheat malt had higher diastatic power (427.03 WK) and lower extractivity (81.85%) compared to Joy barley malt (376.12 WK and 85.79%). Laboratory tests assessing the malts and wort showed that winter barley grain has high malting quality and can be used without modifications in the malting and mashing processes in brewing industry. It is necessary to conduct further research focusing on cultivation, agricultural techniques and technologies applied in wheat farming, in order to obtain cultivars which can be used to produce high quality malts.

Purification, Identification, and Characterization of an Endo-1,4-β-Xylanase from Wheat Malt

In this study, an endo-1,4-β-xylanase was purified from wheat malt following the procedures of ammonium sulfate precipitation, cation-exchange chromatography, and two-step anion-exchange chromatography. The purified endo-1,4-β-xylanase had a specific activity of 3.94 u/mg, demonstrating a weight average molecular weight (Mw) of approximately 58,000 Da. After LC-MS/MS (Liquid chromatography-tandem mass spectrometry) identification, the purified enzyme had the highest matching degree with a GH10 (Glycoside Hydrolase 10) domain-containing protein from wheat, there were 23 match peptides with a score above the threshold and the prot-cover was 45.5%. The resulting purified enzyme was used to investigate its degradation ability on high viscosity wheat-derived water-extractable arabinoxylan (WEAX). Degradation experiments confirmed that the purified enzyme was a true endo-acting enzyme, which could degrade large WEAX into smaller WEAX. The average degree of polymerization (avDP) and the viscosity of WEAX decreased with the increasing reaction time. The enzyme could degrade a small amount of WEAX into arabinoxylan-oligosaccharides (AXOS) with a degree of polymerization of 2-6, but no monosaccharide was produced. The degradation occurred rapidly in the first 3.5 h and decreased with the further prolongation of reaction time.

Application of Water Treated with Low-Temperature Low-Pressure Glow Plasma for Quality Improvement of Barley and Malt

The aim of this study is to determine the quality of water treated with low-temperature, low-pressure glow plasma, either in the air or under nitrogen, in order to obtain high-quality brewer’s malt. To this end, plasma-treated spring water was used for barley grain soaking. In two-row spring barley grain, the procedure provided significantly higher water uptake capacity and grain sensitivity to water, as well as energy and germination capacity. The resulting malt showed improved moisture and 1000-grain mass. Furthermore, laboratory wort produced from the malt by the congress method did not differ statistically from a control sample in terms of filtration time, pH, turbidity, color, extract, free amino nitrogen compounds, and aromatic composition.

Changes in Protein Composition in the Grain and Malt after Fusarium Infection Dependently of Wheat Resistance

The grain yield, as well as the quality and safety of the wheat grains and corresponding malt can be compromised by Fusarium spp. infection. The protein content of the grain affects the chemical composition and enzyme levels of the finished malt. The malting industry demands varieties with good malting and brewing performance, as well as good agronomic performance and disease resistance. The best method of disease control is breeding and selection for resistant varieties. Due to higher requirements for malting wheat worldwide, the goal of this investigation was to explore changes in protein distribution in wheat grains and corresponding malt, which are under higher pressure of Fusarium head blight (FHB) infestation in field conditions. The present study provides new knowledge on the impact of the FHB on the distribution of protein components of naturally Fusarium-infected (control) and Fusarium-inoculated wheat varieties in the grain and the corresponding malt in two consecutive years (2015/2016 and 2016/2017). The results showed that Fusarium infection of the susceptible variety Golubica, decreased total glutenins (5.9%), and both high and low molecular weight glutenin subunits (2.5% and 3.5%, respectively) in wheat grains, compared to control, in 2016. In contrast, gliadins and α-gliadins increased significantly (+7.6% and +5.1%, respectively) in the same variety. Wheat grains of the more resistant variety Vulkan showed an increase of the total glutenins content (+4.3%), and of high and of low molecular weight glutenin subunits (+1.2% and +3.2%, respectively) after Fusarium-inoculation, compared to naturally infected grains in 2016. Susceptible variety Golubica increased total glutenins (+9.1%), and both high and low molecular weight glutenin subunits (+3.5% and +5.6%, respectively) after Fusarium-inoculation in wheat malt, compared to naturally infected malt in 2016. In 2017, when disease pressure was higher than in 2016, there was a tendency in all varieties to increase gliadins and its sub fractions after malting, and to decrease glutenins and its sub fractions in Fusarium-inoculated treatment. In conclusion, FHB dramatically depressed grain yield (up to 37%) and quality (glutenins and high molecular weight subunits) in the susceptible Fusarium variety, which makes it inconvenient for malting.

Enzymatic Properties of endo-1,4-β-xylanase from Wheat Malt

BACKGROUND

Arabinoxylan (AX) is the main non-starch polysaccharide in wheat. Wheat malts are traditional raw materials for beer brewing. AX is divided into water-soluble arabinoxylan (WEAX) and waterinsoluble arabinoxylan (WUAX). In the mashing stage of beer production, WUAX in malt is degraded by arabinoxylanase to WEAX, which is further degraded to smaller molecules and retained in the final beer. The viscosity of WEAX is related to its molecular weight. WEAX with higher molecular weight and viscosity can increase viscosity and turbidity and reduce filtration speed of wort and beer; WEAX with moderate molecular weight and viscosity contributes to the foaming characteristics and foam stability, and promotes the taste and texture of a beer; WEAX with small molecular weight has the functions of anti-tumor and lowering blood pressure and is regarded as a prebiotic. Because WEAXs with different molecular weight and properties have different impacts on the beer brewing process and qualities of the final beer, it becomes more important to control the degradation of AX during the brewing process of a beer. Endo-1,4-β-xylanase (EC 3.2.1.8) is the most important AX degrading enzyme, which cleaves the β -xylosidic bond between two d-xylopyranosyl residues linked in β-(1,4). The study of enzymatic properties of endo-1,4-β-xylanase from wheat malt is very important for the rational formulation of the content and molecular weight of WEAX in wort and beer during the mashing procedure when using wheat malt as the main raw materials.

OBJECTIVE

In this article, our motivation is to study the enzymatic properties (including optimum pH and temperature, pH and temperature stability, the effect of inhibitors) of wheat malt endo-1,4-β-xylanase.

METHODS

In this article, we prepared crude enzyme according to the method of Guo with minor modifications. The endo-1,4-β-xylanase activity was determined according to the method of Biely in the previous report with minor modifications. The 0.5 mL crude enzyme sample was mixed with 0.5 mL 1 mg/mL 4-O-methyl-dglucurono- d-xylan dyed with Remazol Brilliant Blue R (RBBR-Xylan) solution, intensively mixed, and incubated at 40 °C for exactly 90 min. The reaction was stopped by precipitation using 2 mL absolute ethanol, and the reaction mixture was stirred acutely and placed at room temperature for 30 min. Then, the mixture was mixed again and centrifuged at 6000 g for 10 min. The supernatant was collected and the absorbance was measured at 590 nm. Absolute ethanol and RBBR-Xylan were added to the control tubes first, and after the reaction was completed, the crude enzyme sample was added. One unit of endo-1,4-β-xylanase was defined as at pH 5.5 and 40 °C liberate 1 μmol xylose equivalents in 1 min per g dry wheat malt.

RESULTS

The results showed that the optimal activity of endo-1,4-β-xylanase was achieved at pH 5.5-6.0, and the enzyme was extremely stable at pH 4.5, 5.5 and 6.5 after incubation for 30, 50 and 60 min, respectively. The optimal temperature was 40-45 °C and the deactivation temperature was 75 °C. Endo-1,4-β-xylanase was stable at 20 °C and 40 °C; the stability was slightly decreased at 50 °C and rapidly decreased at 55 °C. The enzyme activity was mildly inhibited by K+, Na+, and Pb2+, moderately inhibited by Ca2+, Mg2+ and Mn2+ and severely inhibited by Cu2+, Ag+ and EDTA.

CONCLUSION

We have got the enzymatic properties of endo-1,4-β-xylanase from wheat malt, so during wort mashing, we could apply this research result to carry out the rational formulation of the content and molecular weight of WEAX in wort and beer during the mashing procedure when using wheat malt as the main raw materials. Expected to solve the technical problems such as high viscosity, slow filtration speed and so on, but also highlight the typical flavors of WEAX such as rich and persistent foam and mellow texture during the brewing process of a beer.

Molecular structure-property relations controlling mashing performance of amylases as a function of barley grain size

In brewing, amylases are key enzymes in hydrolyzing barley starch to sugars, which are utilized in fermentation to produce ethanol. Starch fermentation depends on sugars produced by amylases and starch molecular structure, both of which vary with barley grain size. Grain size is a major industrial specification for selecting barley for brewing. An in-depth study is given of how enzyme activity and starch structure vary with grain size, the impact of these factors on fermentable sugar production, and the underlying mechanisms. Micro-malting and mashing experiments were based on commercial methodologies. Starch molecular structural parameters were obtained using size-exclusion chromatography, and fitted using biosynthesis-based models. Correlation analysis using the resulting parameters showed larger grain sizes contained fewer long amylopectin chains, higher amylase activities and soluble protein level. Medium grain sizes released most sugars during mashing, because of higher starch utilization from the action of amylases, and shorter amylose chains. As starch is the substrate for amylase-driven fermentable sugars production, measuring its structure should be a prime indication for mashing performance, and should be used as an industry specification when selecting barley grains for brewing.

Impact of Cereal Seed Sprouting on Its Nutritional and Technological Properties: A Critical Review

Sprouting induces activation and de novo synthesis of hydrolytic enzymes that make nutrients available for plant growth and development. Consumption of sprouted grains is suggested to be beneficial for human health. Positive consumer perceptions about sprouted cereals have resulted in new food and beverage product launches. However, because there is no generally accepted definition of "sprouting," it is unclear when grains are to be called sprouted. Moreover, guidelines about how much sprouted grain material food products should contain to exert health benefits are currently lacking. Accordingly, there is no regulatory base to develop appropriate food labeling for "sprouted foods." This review describes the nutritional and technological properties of sprouted grains in relation to processing conditions and provides guidelines to optimize sprouting practices in order to maximize nutritive value. Relatively long sprouting times (3 to 5 days) and/or high processing temperatures (25 to 35 °C) are needed to maximize the de novo synthesis and/or release of plant bioactive compounds. Nutrient compositional changes resulting from sprouting are often associated with health benefits. However, supportive data from clinical studies are very scarce, and at present it is impossible to draw any conclusion on health benefits of sprouted cereals. Finally, grains sprouted under the above-mentioned conditions are generally unfit for use in traditional food processing and it is challenging to use sprouted grains as ingredients without compromising their nutrient content. The present review provides a basis for better defining what "sprouting" is, and to help further research and development efforts in this field as well as future food regulations development.

Utilização do malte de sorgo na produção de cerveja: revisão bibliográfica

Resumo A cevada (Hordeum vulgare) é o principal cereal utilizado na produção de cerveja, mas é importada, na maioria dos países tropicais e subtropicais. Isto implica no aumento do custo de produção da bebida, além de não satisfazer a demanda das bebidas sem glúten no mercado. O sorgo (Sorghum bicolor L. Moench) é um dos cereais que também podem ser usados na produção de cerveja e, ao contrário da cevada, é livre de glúten, recomendado para doentes celíacos. Assim, recentemente tem aumentado o interesse no uso do malte de sorgo para substituir o malte de cevada na produção de bebidas. No entanto, as principais dificuldades encontradas na produção de bebidas fermentadas a partir de malte de sorgo têm sido o baixo nível de enzimas hidrolíticas e a alta temperatura de gelatinização. O objetivo deste trabalho de revisão foi avaliar os principais fatores que afetam os processos de maltagem (tempo e temperatura de imersão, de germinação e de secagem) e a mosturação com malte de sorgo (pH e temperatura das enzimas, e métodos usados) na produção de cerveja sem glúten.