Influence of malted barley and exogenous enzymes on the glucose/maltose balance of worts with sorghum or barley as an adjunct

The sugar profile of wort from laboratory malted barley, malted sorghum, unmalted barley and unmalted sorghum grains mashed with commercial enzyme preparations were studied. Similar levels of glucose to maltose (1:7) were observed in wort of malted barley and malted sorghum. Mashing barley or sorghum grains with commercial enzymes changed the glucose to maltose ratio in both worts, with a greater change in wort from sorghum grains. Although hydrolysis with commercial enzymes released more glucose from maltose in sorghum wort, the same treatment retained more maltose in barley wort. Adding malted barley to sorghum grains mashed with commercial enzymes restored the glucose to maltose ratio in sorghum mash. Fermentation of wort produced from all barley malt (ABM) mash and commercial enzyme/barley malt/sorghum adjunct (CEBMSA) mash of similar wort gravity was also studied. ABM and CEBMSA worts exhibited similar glucose to maltose ratios and similar amino acid spectra. However, ABM released more individual amino acids and five times more proline than wort from commercial enzyme/barley malt/sorghum adjunct. ABM produced 27% more glucose and 7% more maltose than CEBMSA. After fermentation, ABM mash produced 9.45% ABV whilst commercial enzyme/barley malt/sorghum adjunct mash produced 9.06% ABV. Restoration of the glucose/maltose ratio in the CEBMSA mash produced wort with a sugar balance required for high gravity brewing. © 2020 The Institute of Brewing & Distilling     

Changes in Sorghum Malt During Storage

The diastatic power of the freshly kilned sorghum malt at 68.1°WK had a 29% drop after six months of storage. Freshly kilned sorghum malt displayed high wort turbidity (4.9 EBC) which dropped to 0.95 EBC and 1 EBC after 2 and 6 months of storage respectively. The colour of the malt worts faded slightly over the trial period from 7.6 EBC in freshly kilned malt to 6.8 EBC after six months. Extract remained fairly steady throughout the study period most likely due to the use of external amylolytic enzymes during mashing. The protein in extract/protein in grain fluctuated between 46.6% in the freshly kilned malt to 43.2% at the end of six months. The apparent extract after final attenuation (AEFA) indicates more fermentability beginning from two months after storage. Free α‐amino nitrogen (FAN) dropped from 238 mg/L to 194 mg/L after six months of storage. Mash filtration with a micro‐mash filter remained prolonged (86–93 min) throughout the six months of storage.     

Effect of malting regimen on diastatic power,cold and hot water extracts of malts from sorghum

In this study, sorghum grains were malted using different malting regimens and the malt qualities were analysed for cold water extract (CWE), hot water extract (HWE) and diastatic power (DP). Results showed that malting regimen produced sorghum malts with peak CWE, HWE and DP within the pre-determined limits of malting regimen. From this, predictive models of sorghum malt quality were developed and tested. Whilst steeping duration interacts significantly with the germination period to cause variations in CWE and HWE, only the germination period significantly influenced the DP of sorghum malts. However, the kilning temperature showed no significant impact on the parameters studied. Besides CWE, HWE and DP correlating positively with each other, the developed predictive models were significant (P < 0.05) and satisfy the quality of fit (R² > 0.70) of the proposed models. The result demonstrated that wort for different purposes can be obtained by varying the malting operational conditions in the predictive model, thus saving time, resources, preliminary studies and research designs. Besides the promotion of a cheaper local alternative material for industrial wort production and brewing purpose, this research provides valuable insight on the brilliant prospect of variable malting regimen in predicting and adjusting the quality characteristics of sorghum malt and wort. Future studies are required to develop models for wort produced from peak CWE, HWE and DP, for predicting wort quality characteristics.     

Infrared spectral analysis of sugar profiles of worts from varying grist to liquor ratios using infusion and ramping mash styles

Fermentability is an important trait for the brewing industry. Current industry methods lack the predictive capacity to accurately estimate how well a wort will ferment in the brewhouse. Wort from two mashing styles (high‐temperature infusion and low‐temperature ramping), and under varying grist to liquor (G:L) ratios, were produced and the differences in maltose, maltotriose and glucose were measured. The two mashing styles showed differences in original extract (Plato) values between the G:L ratios with a 1:2 G:L having the highest original extract. Maltose was the most abundant sugar in all sample types. All worts were scanned using Fourier transform infrared (FTIR) and the spectra also showed differences between the original extract and final extract with most of the changes around the spectral region associated with carbohydrates, a result of sugar utilization by the yeast. FTIR calibrations for extract and fermentable sugars all had r² values >0.98, with ratio of standard error of prediction to standard deviation >5. The results indicated changing fermentable sugar levels, thus making a prediction of fermentability possible. The FTIR also provided a rapid measure of changes in the fermentable sugar profile, which could assist maltsters and brewers in monitoring malt and beer quality. Copyright © 2016 The Institute of Brewing & Distilling     

Quality Control of Malt: Turbidity Problems of Standard Worts Given by the Presence of Microbial Cells

Since the main effect on beer colour originates from the chemical composition of malt, the measurement of the colour of wort obtained from malt is one of the most important quality parameters to be controlled. Malt colour determination is usually performed spectrophotometrically on EBC Congress worts, which are generally bright. The quality control on the malt harvested in the year 2007 highlighted a problem of turbid Congress wort, for a part of Northern Europe samples analyzed, and therefore the spectrophotometric determination of the colour of wort was not possible. Thus both analytical screening of the quality parameters of malt and the scanning electron microscope (SEM) were used to identify the nature of the turbidity in the worts. The results obtained suggested that the nature of the turbidity of Congress worts could have been due to microbial contamination of the barley, enhanced in particular by the rainy harvest and the consequent formation of exopolysaccharides (EPS) by stressed yeast and bacteria during malting.     

Micromalting triticale: Optimising processing conditions

Small-scale trials were carried out to optimise the conditions for micromalting triticale grain, using three varieties grown in the UK. Compared with barley, triticale grains required short steeping periods with a short air rest. They malted rapidly, and produced malts with high hot water extracts after 4 or 5 days' germination. Applications of gibberellic acid and potassium bromate during malting significantly altered the qualities of malts. Gibberellic acid increased hot water extracts, soluble nitrogen levels and malting losses. When the additives were used in combination, high hot water extracts were obtained and malting losses were reduced relative to controls, but unexpectedly the level of total soluble nitrogen was elevated and did not significantly differ from that obtained using gibberellic acid alone. Both additives usefully reduced wort viscosities, which were unacceptably high by barley malt brewing standards. Wort separation from small-scale mashes was slow.     

LABORATORY PREDICTION OF BREWHOUSE EXTRACT AND PERFORMANCE

Malts have been analysed during the micromalting of a number of barley varieties by a fine-concentrated extract difference procedure and by a 70°C mash viscosity method. Varietal differences were found using both procedures. The use of these two methods to predict brewhouse performance has been assessed on the pilot brewery scale in experiments carried out over three seasons. Results indicate that the 70°C viscosity method is useful in assessing the viscosity of strong worts, while the fine-concentrated extract difference method gives an excellent estimate of the extract achievable from the malt.     

Analysis of malts by capillary electrophoresis

A range of malts, as well as their high‐ and low‐molecular‐mass fractions, has been examined by capillary electrophoresis in phosphate buffer, pH 2.5, and in carbonate buffer, pH 9.5, and the results have been compared with those for roasted barley and for caramels. The malts fall into two categories: (i) the lightly roasted malts, where the high‐molecular‐mass coloured fraction is negatively charged at pH 9.5 and positively charged at pH 2.5; and (ii) the highly roasted malts (and the roasted barley), where the high‐molecular‐mass fraction migrates close to the electro‐osmotic flow at both pH 9.5 and 2.5, implying that it carries little or no charge. The former category shows migration patterns similar to Class III caramels, whereas the latter migrates differently from Class I, III and IV caramels as well as from the former. Capillary electrophoresis therefore has considerable potential for differentiating between malts and between malts and caramels and roasted barley. © 2002 Society of Chemical Industry     

Effects of mashing on total phenolic contents and antioxidant activities of malts and worts

Effects of mashing on total phenolic contents (TPC), radical‐scavenging activity, reducing power and metal chelating activity of malts and corresponding worts were clarified in this study. Results showed that there were significant variations in TPC and antioxidant activity across malts and worts. An 8.8% of increase in TPC was observed during the early stage of mashing, accompanied by an increase in antioxidant activity. However, 2.6% of decrease in TPC and inconsistent changes in antioxidant activity were found during the mashing at higher temperature. Overall, mashing resulted in 6.0% and >10.0% of increases in TPC and antioxidant activity, respectively. Moreover, Pearson correlation analysis revealed that there were good correlations (ranging from 0.622 to 0.735, P < 0.01) between TPC and antioxidant activity of malts and worts. Additionally, mashing resulted in more positive correlations between TPC and antioxidant activity, emphasising the key role of malt phenolic compounds for wort antioxidant activity.     

六通道麦汁全自动分析仪及其应用

本文介绍了间断式流动分析系统的基本原理和应用于麦芽分析中的分析原理和方法，开发了α-氨基氮。总氮、可溶性氮和库尔巴哈值；糖化力α-淀粉酶；β-葡聚糖；浸出率和粗细粉差等六个方面的九个主要指标分析，提高了实验室麦芽分析的速度和准确性。     

Use of triticale flours in cracker-making

In general, triticale is not a good raw material for bread making. However, some varieties produce flours of good quality for cookie production. It is a well-known fact that cracker quality depends on the flour used for cracker production. All over the world, a blend of hard and soft wheat is used; however, the use of soft flour is recommended. Since additional soft wheat cultivation is not allowed in Argentina, triticale represents a good alternative for cracker production. In the present study 15 triticale cultivars and a flour of optimum cracker quality were used to produce crackers in order to establish criteria to evaluate flour quality in cracker-making. The factors that determine cracker quality, as well as the relationships between different quality parameters were investigated. Electrophoretic patterns of triticale proteins extracted from flours were determined. Five cultivars produced crackers of similar quality to that of standard flour of industrial good quality. A protein band with a 110 kDa molecular mass influenced flour quality, measured as the ratio of the mean between weight and length, WL and the height of ten crackers (H₁₀), WL/H₁₀, while other flour constituents such as pentosans, soluble proteins and damaged starch could affect its weight.     

精酿啤酒专用麦芽的研究进展

在工业啤酒日趋饱和的大背景下,精酿啤酒在中国受到越来越多消费者的喜爱,并呈现出广阔的成长空间。麦芽作为精酿啤酒重要原料之一,其品质优劣决定了啤酒品质的好坏。该文结合当前精酿啤酒专用麦芽的应用研究,总结、归纳了精酿啤酒酿造用麦芽的基本种类、制麦工艺、麦芽风味物质及麦芽主要成分对啤酒品质的影响,最后阐述了精酿啤酒专用麦芽对麦芽加工工业和精酿啤酒制造业的重要意义,并对精酿啤酒专用麦芽的前景进行了展望。     

The Application of Near Infrared Spectroscopy to Evaluate Malting Quality

Near infrared (NIR) spectroscopy is a rapid technique which is used within plant breeding programs for the analysis of many grain traits. This study investigated the application of NIR analysis of wort samples to select malting quality cultivars in a barley breeding program. An automatic sampling and data capture system was developed which consisted of a Perten filter NIR instrument with a flow through cell module operating in transflectance mode interfaced with a computer, peristaltic pump and sample changer. Calibrations for hot water extract, free alpha-amino nitrogen and soluble protein were developed using multiple linear regression analysis based on four wavelength terms for each trait. The correlation coefficients for both calibration and prediction data sets were highly significant (P<0.01) and the standard error of prediction was similar to that obtained by standard methods. Cultivars with known malting quality were included in the experiments and their ranking by NIR was consistent with the standard methods. The reported calibrations have been used for over four years to screen early generation breeding lines for malting quality.     

小黑麦啤酒糖化工艺的探讨

首次采用了小麦与黑麦属间异源多倍体杂交品种——小黑麦作为酿造啤酒原料。与传统啤酒大麦原料相比 ,小黑麦不仅淀粉酶活性及蛋白质含量高 ,八种必需氨基酸平衡 ,而且产量高 ,种植费用低 ,可降低原料价格。本试验对小黑麦糖化工艺进行了探讨 ,确定糖化主要技术参数 ,麦汁质量符合酿造啤酒标准。     

Physico-chemical characteristics and non-starch polysaccharide contents of Indica and Japonica brown rice and their malts

Brown rice malt from Indica and Japonica type rice were prepared and their nutrient composition as well as non-starch polysaccharide (NSP) contents and also some of the physico-chemical characteristics were determined. The activity of α- and β-amylases in the ungerminated (native) rice was negligible but increased considerably on germination. Malting altered the chemical composition of both Indica and Japonica rice to a small extent but caused noticeable changes in the pasting characteristics. The free sugars and water-soluble non-starch polysaccharide (NSP) contents of the malt samples were considerably higher than the native samples. The carbohydrate elution profile of native and malted rice on Sepharose CL-2B revealed partial degradation of starch. However, the electrophoresis patterns of the native and malt samples were comparable but exhibited decrease in their band intensity. The study revealed that, controlled germination or malting causes considerable changes in the physico-chemical and bio-chemical properties of both Indica and Japonica rice.     

不同种类麦芽对下面发酵啤酒酿造风味的影响

为了从源头控制下面发酵啤酒的发酵生产并提高其品质,通过啤酒发酵模拟体系,系统评价英国麦芽（Eng）、加拿大麦芽（Can）和德国麦芽（Ger）对下面发酵啤酒酿造风味的影响。分别测定了3种麦芽的品质指标及所酿啤酒的理化指标;并采用顶空固相微萃取（HS-SPME）和气相色谱质谱联用（GC-MS）法检测了所酿啤酒中风味物质组成和含量上的差异。结果表明,加拿大麦芽的库尔巴哈值（45%）、浸出率（≥77%）、糖化力（414 WK）和α-氨基酸态氮（118 mg/L）等品质指标和酒精度（2.97%vol）、原麦汁浓度（8.63 °P）、实际浓度（2.76%）、外观浓度（1.17%）、实际发酵度（67.97%）和外观发酵度（86.41%）等所酿啤酒的理化指标适中,啤酒中风味物质种类多样（75种）、相对含量丰富（271.82%）、比例协调,是最适合酿造Lager啤酒的麦芽种类。该结果可为高品质啤酒的工业化生产提供理论依据。     

Isolation and characterisation of the bacteriocin-producing Leuconostoc citreum HW02 from malts

Herein, a lactic acid bacterium which produces bacteriocin was isolated from malted barley. The isolated strain was identified by 16 S rRNA analysis and designated Leuconostoc citreum HW02. Bacteriocin HW02 was shown to have growth inhibition against health-threatening Gram-positive microorganisms such as Staphylococcus aureus, Listeria monocytogenes, and Latilactobacillus curvatus. Bacteriocin HW02 was reported to be incapable of inhibiting the growth of health-threatening microorganisms after treatment with proteolytic enzymes; thus, it was indicated that bacteriocin is proteinaceous in nature. Bacteriocin HW02 showed stability against a broad range of temperatures (60–121 °C), pH (2–10), various detergents, or organic solvents. Its antimicrobial activity against the indicator strain, Lactiplantibacillus plantarum NCDO 955, was maximised (320 AU mL⁻¹) midway through the stationary phase at 12 h. The crude bacteriocin HW02 molecular weight was estimated to be about 7.7 kDa. After the treatment of the indicator strain with bacteriocin, the maintenance of the optical density of the culture, the morphological analysis of cell-structure abnormalities, and cell shrinkage implied that bacteriocin showed bactericidal activity.     

非淀粉多糖酶改善麦汁品质的研究

在常规的麦汁制备过程中加入非淀粉多糖(NSP)酶,研究该酶对麦汁品质的影响。方差分析结果表明,酶的添加量、添加温度和作用时间对麦汁的过滤速度、糖化时间、还原糖、总氮、α-氨基氮和麦汁收率均有显著影响(p<0.05)。试验确定NSP酶添加的最佳工艺条件为:添加量1.00%,添加温度45℃,作用时间为20min。     

加酶制备燕麦麦汁的正交试验研究

以燕麦为辅料制备麦芽汁,采用正交试验设计研究酶的添加量、添加阶段、作用时间、辅料添加量对麦芽汁品质的影响。结果表明,NSP酶的添加量对麦汁的过滤时间、糖化时间、α-氨基氮含量、还原糖量和收得率均有显著性影响（p〈0．05）,NSP酶的添加阶段和燕麦添加量均只对麦汁中仅一氨基氮含量有显著性影响（p〈0．05）,而NSP酶的作用时间对测定的理化指标均无显著性影响（p〉0．05）。最佳工艺条件为NSP复合酶添加量为0．24％,燕麦添加量为30％,NSP复合酶在蛋白质休止的第一阶段（45℃）添加,保温23min。