Malting Properties Research Articles

Wet vacuum impregnation assisted in malting; its implication on steeping degree, germination energy and malt properties

SummaryThe wet vacuum impregnation (WVI) was used in malting process to reduce soaking period. To implement WVI during steeping, vacuum pressure of 500 mmHg for 300 s, was applied twice on five Thai barley cultivars. The effect of WVI on germination energy, moisture content, phenolic acids, antioxidant activity (AOA) and malt quality were examined relative to Central European Commission for Brewing Analysis (MEBAK) malting condition. Moisture content in barley soaked by WVI and MEBAK steeping method were in the range of 36.1–39.9% and 39.9–47.8%, respectively with germination energy of 96–97%. The physicochemical properties of malt from steeping via WVI and MEBAK showed the malts were protein‐rich cultivars, adequate β enzyme and low α amylase activities, hence, low‐malt extract. Total fermentable sugars were relative higher in MEBAK malts than WVI malts. Nevertheless, steeping by WVI had higher free and bound phenolic acids, which led to higher AOA via ABSTS and DPPH assays in some barley cultivars than MEBAK. This research highlights the WVI did not limit barley gemination and the potential of this technology in malting process by limiting steeping time. Further study is required to reduce air‐rest period and optimise condition to achieve moisture content of 40–45% in soaked barley.

Natural variation in HvAT10 underlies grain cell wall-esterified phenolic acid content in cultivated barley.

The phenolic acids, ferulic acid and p-coumaric acid, are components of plant cell walls in grasses, including many of our major food crops. They have important health-promoting properties in grain, and influence the digestibility of biomass for industrial processing and livestock feed. Both phenolic acids are assumed to be critical to cell wall integrity and ferulic acid, at least, is important for cross-linking cell wall components, but the role of p-coumaric acid is unclear. Here we identify alleles of a BAHD p-coumaroyl arabinoxylan transferase, HvAT10, as responsible for the natural variation in cell wall-esterified phenolic acids in whole grain within a cultivated two-row spring barley panel. We show that HvAT10 is rendered non-functional by a premature stop codon mutation in half of the genotypes in our mapping panel. This results in a dramatic reduction in grain cell wall-esterifed p-coumaric acid, a moderate rise in ferulic acid, and a clear increase in the ferulic acid to p-coumaric acid ratio. The mutation is virtually absent in wild and landrace germplasm suggesting an important function for grain arabinoxylan p-coumaroylation pre-domestication that is dispensable in modern agriculture. Intriguingly, we detected detrimental impacts of the mutated locus on grain quality traits where it was associated with smaller grain and poorer malting properties. HvAT10 could be a focus for improving grain quality for malting or phenolic acid content in wholegrain foods.

Low-cost production and healthy preservation of malt drink using Melkassa-7 and Moringa oleifera leaf extract

Currently, there has been an increased interest in the beverage industry to produce gluten-free, low-alcohol drinks with increased shelf life. Maize is a widely grown and most versatile cereal to produce cost effective brewery products by replacing its conventional raw material, barley. In this present study a non-toxic and low-cost nutritious malt drink was prepared using Melkassa-7 (yellow maize) and is preserved using a novel, healthy, and eco-friendly preservative extracted from Moringa oleifera. The quality of the selected cereal was estimated in terms of proximate analysis and its malting properties was expressed as thousand kernel weight, malting loss, germination capacity and energy. The mashing process was optimized and a robust model was developed. The final malt drinks were formulated with 5%, 10%, and 15% of the preservative. The physio-chemical analysis of the three drinks was performed and verified with the standards. Anti-microbial effect and shelf life were estimated using three important spoilage microbes, yeast, coliforms, and Escherichia coli. Further, sensory characteristics were tested using a panel of six professional tasters from Dashen brewery. Finally, as prepared product was compared with Luse, a standard product of Dashen brewery.

Methods for suppressing Fusarium infection during malting and their effect on malt quality

The incidence of Fusarium head blight (FHB) in cereal grains such as barley and wheat is of growing concern due to climate change threatening food safety. Further processing of cereals by malting provides an ideal environment for the growth of Fusarium, leading to food safety concerns due to the production of mycotoxins, production challenges with the negative effects to malt and beer qualities, and economic loss owing to the field yield reduction. To improve food safety and product quality, different methods of fungal control have been investigated and reported in the literature. Traditional methods to control fungal growth and mycotoxin production have included chemical and physical methods, but these treatments led to worsened malt properties, limiting their applicability to the brewing industry. Biological control methods have, therefore, attracted wide interest as alternative treatments due to their ability to limit Fusarium growth and mycotoxin production in malting cereals without toxic by-products, thus exhibiting promise for improving food safety. Various biological agents have been investigated and applied in malting and have shown the potential to suppress Fusarium spp. growth and mycotoxin production. These agents include several lactic acid bacterial (LAB) species and Geotrichum candidum. Another promising biocontrol agent for malting control is Pythium oligandrum, which has successfully limited Fusarium infection in other agricultural crops. The review outlines the Fusarium-control methods reported referenced for the brewing industry and the present prospects in biological control applications on the promise of P. oligandrum as a novel agent for malting.

ИССЛЕДОВАНИЕ СОЛОДОВЕННЫХ СВОЙСТВ КАЗАХСТАНСКИХ СОРТОВ ЗЕРНА ТРИТИКАЛЕ ДЛЯ ИСПОЛЬЗОВАНИЯ В ИНДУСТРИИ НАПИТКОВ

Today the beverage industry occupies an important place in the processing industry of the Republic of Kazakhstan and is one of the most attractive investment sectors of the economy. However, this industry is still not provided in sufficient quantities with its own, domestic high-quality raw materials - rye and / or barley malt. For example, fermented malt is used as a source of colors and aromas. It is the main raw material in the preparation of kvass, kvass wort concentrate and kvass bread, the rate of application of this type of malt is from 40 to 60%, depending on the method of production of this type of product. The processing of cereals with a high protein content (above 12%) and a low starch content and extractiveness is economically disadvantageous, and undesirable from a quality point of view. The most important directions in solving this problem should be recognized as the improvement and development of new resource-saving technologies of malt using non-traditional types of raw materials. Currently, the use of triticale grain in the fermentation industry in the production of malt and the further replacement of traditional types of malt for the preparation of alcohol, beer, kvass is promising. In recent years, new varieties of triticale have been obtained in the Republic of Kazakhstan, which are distinguished by high technological properties, which are included in the State Register. In this regard, it is obvious that the performance of work related to theoretical and experimental research aimed at the development of new technological modes of preparation of malt from triticale is one of the urgent tasks, the decision of which, to create an assortment of drinks. The purpose of the research work is to study the malting properties of Kazakhstani varieties of triticale grain.

Barley Malt Esterification after Ultrasound and Stearic Acid Treatment: Characterization and Use as Stabilizing Agent in Oil-in-Water Emulsions

This work aimed to obtain novel materials from malt modification for using in oil/water emulsions. Malt was modified using stearic acid (2% w/w) in combination with different energy densities (33.8 × 106, 60 × 106, 72.5 × 106, and 107.5 × 106 J/m3) from ultrasound probe resulting in four materials. These materials were characterized by degree of substitution (DS), amylose content, dextrose equivalent (DE), protein content, solubility, thermal properties, Fourier-transform infrared spectroscopy (FT-IR), crystallinity analysis by X-ray diffraction, and scanning electron microscopy. Emulsions containing 15% total solids (25% canola oil and 75% modified malt as stabilizing agent) were prepared and characterized. Results showed that increasing energy densities produced different effects on malt properties due to an increase in DS, amylose content, and DE values. The sonication process in combination with stearic acid increased malt solubility and the gelatinization temperature of malt, caused modifications of starch crystallinity in the amorphous region and hydrolysis of starch granules, and promoted good stabilizing properties for emulsions containing modified malt.

Effect of Experimental Variables on the Malting Performance of Nigerian Maize Oba Super 2 Variety

Background: The Nigerian cultivar, Oba Super 2 (OS2) maize is inexpensive but under- utilized owing to poor development of malting technology for brewing.
 Aim: To study the effects of experimental variables on the malting performance of Nigerian maize Oba Super 2 variety.
 Study Design: Exploratory.
 Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Nigeria, between March, 2018 to September, 2019.
 Methodology: Certified Oba Super 2 maize variety was obtained from Premier Seed Limited, Zaria. The grain sample was malted at varying steeping (S) period (S30, S36 and S42 hours), different germination (G) period (0, 1, 2, 3, 4 and 5 days) and varying kilning (K) temperatures (45, 50 and 55°C) to determine the malting performance. The properties of the un-malted and malted maize were determined using standard methods. Data were analysed using analysis of variance (ANOVA) at P < 0.05.
 Results: The malting loss (ML) was significantly higher (P < 0.05) at different steeping period, on the fifth day of germination (G5). The cold water extract (CWE) was significantly higher (P < 0.05) on the fourth day of germination (G4) kilned at K50. The values for hot water extract (HWE) were significantly higher (P < 0.05) on the G4 at K45, K55 and K50, respectively, while free alpha amino nitrogen (FAN) values were significantly higher (P < 0.05) on the G4, all kilned at K50. The values for diastatic power (DP) were significantly higher (P < 0.05) on the G5, kilned at K50, while the cold water soluble protein (CWS-P) was significantly higher (P < 0.05) on the G3 kilned at K50.
 Conclusion: The results indicated that longer steeping and germination periods as well as moderate kilning temperature contributed maximally in improving the malting properties and high extract yields.

Dependence of malt properties of barley on the effect of foliar fertilization of plants with microfertilizers

Dependence of malt properties of barley on the effect of foliar fertilization of plants with microfertilizers

The Influence of Wheat Malt Quality on Final Attenuation Limit of Wort

This paper aimed to investigate the influence of certain wheat and wheat malt quality indicators on limit of attenuation of wort (LAT). The experiment was conducted using wheats that have been proven to display the best malting properties with heightened total and soluble N and very good viscosity. Standard micromalting and brewing processes and analysis were applied. The obtained results showed that the quality of analyzed malts was satisfying. Statistical analysis determined no significant correlation between the limit of attenuation of wort and any of the other analyzed quality indicators. The lack of close correlations between indicators is probably due to the extremely complex intertwine of factors influencing the LAT, pointing to the fact that this particular indicator should be observed as separate and mainly variety-dependent.

Preliminary study in improving the malting properties of Dawa, local Sorghum (Sorghum vulgare) variety.

Improving the malting properties of local sorghum [Dawa] (sorghum vulgare) was investigated. Malting is the germination of cereal gain in moist air under controlled conditions, the primary objective being to promote the development of enzymes which are not present in the ingeminated grain. Steeping, germination and kilning temperatures and conditions were altered to affect the improvement of the malt to be produced. Aseptic conditions were employed to avoid contamination of the process. A steeping regime of 52 hours was adopted. The steeping cycle involves 22 hours water steep and 8 hours air rest. Germination was done for 5 days during which enzymes development took place. Kilning was done in an oven for 24 hours at 500C so as to arrest germination. After these, grain and malt analyses were carried out. During the analyses, the following results were obtained: Moisture content (5.4%), thousand corn weight (28.5g), Germinative energy (95.5%), Germinative capacity (90%), cold water extract (44.8%), hot water extract (23%) and malting loss (13%). The result obtained shows that the sorghum variety had high malting loss which was attributed to the high germination temperature used. Also from the result, a Germinative capacity of 90% was gotten. This makes the sorghum (Dawa) variety a good grain raw material for brewing.

Evaluation of malting properties and activities of three enzymes from sorghum (Sorghum bicolor) during malting

Sorghum (Sorghum bicolor (L) Moench), is used as human food such as bread, malt drinks and beers; as livestock feed, renewable energy source such as bioethanol. The experimental monitoring of enzyme activity during malting permits the detection of germination-specific genes. The products of α- amylase (simple sugars), β-amylase (maltose), protease (free amino nitrogen) and polyphenol oxidase (quinone), combined during kilning and mashing, with the development of characteristics flavor and coloured malt. In this study, we investigate malting properties of white and yellow varieties of sorghum while the variation in the activity of the three enzymes namely polyphenol oxidases, amylases and proteases, were monitored as the malting progresses. The result obtained were 95% and 86% germinative energy, 1.49 g and 1.09 g water absorption, 0.751 mg/ml and 0.639 mg/ml crude protein for yellow and white sorghum respectively. The activity of the three enzymes was higher in dormant yellow sorghum than dormant white sorghum. For both varieties, polyphenol oxidase activities were lowest during steeping than in dormant grain, while the highest activities were obtained during germination. Amylases activity did not changed significantly from dormant to germination. The proteases activities were highest during steeping than in dormant while gradually decreased to zero level during germination.

Feasibility study on the use of attenuated total reflectance infrared spectroscopy as high throughput screening tool to phenotype single barley seeds (Hordeum vulgare L.)

Knowledge of the chemical and structural differences between barley (Hordeum vulgare L.) varieties and breeding lines might lead to an understanding of the reasons for these differences among genotypes in relation to their malting properties. The aim of this study was to evaluate the use of attenuated total reflectance mid infrared (ATR-MIR) spectroscopy combined with univariate and multivariate methods as a high throughput screening tool to phenotype single seeds of barley. Varieties that yield high malting quality (hot water extract (HWE) > 80%) showed relatively high non-structural carbohydrates (e.g. starch) to protein and non-structural to structural (e.g. cellulose) carbohydrates ratios compared with those samples having moderate HWE (78% < HWE < 80%). The use of ATR-MIR spectroscopy and in particular the use of ratios at specific wavenumbers can provide useful information about the biophysical and chemical characteristics of the grain.

Development of SNP markers for genes of the phenylpropanoid pathway and their association to kernel and malting traits in barley.

BackgroundFlavonoids are an important class of secondary compounds in angiosperms. Next to certain biological functions in plants, they play a role in the brewing process and have an effect on taste, color and aroma of beer. The aim of this study was to reveal the haplotype diversity of candidate genes involved in the phenylpropanoid biosynthesis pathway in cultivated barley varieties (Hordeum vulgare L.) and to determine associations to kernel and malting quality parameters.ResultsFive genes encoding phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), chalcone synthase (CHS), flavanone 3-hydroxylase (F3H) and dihydroflavonol reductase (DFR) of the phenylpropanoid biosynthesis pathway were partially resequenced in 16 diverse barley reference genotypes. Their localization in the barley genome, their genetic structure, and their genetic variation e.g. single nucleotide polymorphism (SNP) and Insertion/Deletion (InDel) patterns were revealed. In total, 130 SNPs and seven InDels were detected. Of these, 21 polymorphisms were converted into high-throughput pyrosequencing markers. The resulting SNP and haplotype patterns were used to calculate associations with kernel and malting quality parameters.ConclusionsSNP patterns were found to be highly variable for the investigated genes. The developed high-throughput markers are applicable for assessing the genetic variability and for the determination of haplotype patterns in a set of barley accessions. The candidate genes PAL, C4H and F3H were shown to be associated to several malting properties like glassiness (PAL), viscosity (C4H) or to final attenuation (F3H).

The influence of steep regime and germination period on the malting properties of some hull-less barley lines

Following field trials in 2008 and 2010, six lines, derived by mutation in the hull-less barley cultivar Penthouse, were selected to provide a range in grain β-glucan content. These lines, along with Penthouse and the hulled, malting variety Optic, were then malted, using four different steeping regimes, with samples kilned after 3, 4 and 5 days of germination. The longest steep regime provided samples with optimum modification after 5 days of germination. Samples from the other steep regimes were under-modified to varying degrees. In particular, the steeps with a single immersion gave poorly modified samples with low extracts and alcohol yields. One line, with low grain β-glucan, gave higher alcohol yields than either Penthouse or Optic, following a regime comprising two short immersions and a single air-rest, but there was no clear association, within the lines, between β-glucan content and malting properties. Copyright © 2012 The Institute of Brewing & Distilling

Yeasts in malting, with special emphasis on Wickerhamomyces anomalus (synonym Pichia anomala)

Malted barley is a major raw material of beer, as well as distilled spirits and several food products. The production of malt (malting) exploits the biochemical reactions of a natural process, grain germination. In addition to germinating grain, the malting process includes another metabolically active component: a diverse microbial community that includes various types of bacteria and fungi. Therefore, malting can be considered as a complex ecosystem involving two metabolically active groups. Yeasts and yeast-like fungi are an important part of this ecosystem, but previously the significance of yeasts in malting has been largely underestimated. Characterization and identification of yeasts in industrial processes revealed 25 ascomycetous yeasts belonging to 10 genera, and 18 basidiomycetous yeasts belonging to 7 genera. In addition, two ascomycetous yeast-like fungi belonging to the genera Aureobasidium and Exophiala were commonly detected. Yeasts and yeast-like fungi produced extracellular hydrolytic enzymes with a potentially positive contribution to the malt enzyme spectrum. Several ascomycetous yeast strains showed strong antagonistic activity against field and storage moulds, Wickerhamomyces anomalus (synonym Pichia anomala) being the most effective species. Malting studies revealed that W. anomalus VTT C-04565 effectively restricted Fusarium growth and hydrophobin production during malting and prevented beer gushing. In order to broaden the antimicrobial spectrum and to improve malt brewhouse performance, W. anomalus could be combined with other starter cultures such as Lactobacillus plantarum. Well-characterized microbial mixtures consisting of barley and malt-derived microbes open up several possibilities to improve malt properties and to ensure the safety of the malting process.

Yeasts isolated from industrial maltings can suppress Fusarium growth and formation of gushing factors

Fusarium infection of barley and malt can cause severe problems in the malting and brewing industry. In addition to being potential mycotoxin producers, Fusarium fungi are known to cause beer gushing (spontaneous overfoaming of beer). Cereal-derived bacteria and yeasts are potential biocontrol agents. In this study, the antifungal potential of selected yeasts (12 strains) derived from the industrial malting ecosystem was studied in vitro with a plate-screening assay. Several ascomycetous yeast strains showed antagonistic activity against field and storage moulds, Pichia anomala being the most effective strain. The effects of P. anomala VTT C-04565 (C565) were examined in laboratory scale malting with naturally contaminated barley exhibiting gushing potential. P. anomala C565 restricted Fusarium growth and hydrophobin production during malting and prevented beer gushing. Grain germination was not disturbed by the presence of yeast. Addition of P. anomala C565 into the steeping seemed to retard wort filtration, but the filtration performance was recovered when yeast culture was combined with Lactobacillus plantarum VTT E-78076. Well-characterized microbial cultures could be used as food-grade biocontrol agents and they offer a natural tool for tailoring of malt properties.

Indigenous Microbial Community of Barley Greatly Influences Grain Germination and Malt Quality

The present study was carried out to investigate the impacts of bacterial and fungal communities on grain germination and on the malting properties of good-quality two-row barley. In order to suppress the growth of bacterial and/or fungal communities, various antibiotics were added to the first steeping water of barley. This study was also designed to explore the dynamics of the bacterial community in the malting process after antimicrobial treatments by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The diverse microbial community played an active role in the malting ecosystem. Even previously undescribed bacterial species were found in the malting ecosystem. Suppression of the bacterial community mainly consisting of Gram-negative bacteria was advantageous with respect to grain germination and wort separation. In addition, more extract was obtained after antibacterial treatments. The fungal community significantly contributed to the production of microbial β-glucanases and xylanases, and was also involved in proteolysis. An improved understanding of the complex microbial community and its role in malting enables a more controlled process management and the production of high quality malt with tailored properties.

Lactobacillus plantarum and Pediococcus pentosaceus Starter Cultures as a Tool for Microflora Management in Malting and for Enhancement of Malt Processability

Lactobacillus plantarum VTT E-78076 (E76) and Pediococcus pentosaceus VTT E-90390 (E390) starter cultures were added to the steeping water of normal malting barley in order to balance the microbial community and to enhance malt processability. In this study, we also investigated the effects of lactic acid-acidified MRS-spent medium (MRS-LA) on malting performance. Malting trials with five different two-row barley varieties were carried out in 25 kg pilot scale. The starter cultures promoted yeast growth during malting and restricted the growth of harmful bacteria and Fusarium fungi. Furthermore, they had positive effects on malt characteristics. Reduction in wort viscosity and beta-glucan content and enhanced xylanase and microbial beta-glucanase activities were observed. Starter cultures notably improved lautering performance. Some of the beneficial effects were due to the lactic acid and low pH, as similar effects were obtained with MRS-LA. Starter cultures offer a tool for tailoring of malt properties.

Molecular characterization of mlo mutants in North American two‐ and six‐rowed malting barley cultivars

SUMMARY Barley lines PRU1, URS1 and URS2 represent three candidate mlo mutants induced in either the two-rowed cultivar Prudentia or the six-rowed cultivar Ursula. Both Prudentia and Ursula are North American malting barley varieties with specific malting properties. Here, we analysed the three candidate mutants at the molecular level. We identified lesions in the Mlo gene of all three lines, causing either a premature stop codon (PRU1), a shift in the reading frame (URS1) or a single amino acid replacement (URS2). In a transient gene expression assay, the URS2 mlo allele fails to complement a barley null mutant genotype, indicating that URS2 is a genuine mlo mutant (here designated as mlo-33). The MLO-33 mutant variant accumulates to similar levels as the wild-type MLO protein in Arabidopsis protoplasts, suggesting that MLO-33 is stable in planta. We show that the mlo-33 allele can be readily detected in barley genomic DNA by a cleaved amplified polymorphic sequence marker, rendering this allele particularly suited for marker-assisted breeding.

Wheat Variety and Barley Malt Properties: Influence on Haze Intensity and Foam Stability of Wheat Beer

Laboratory wheat beers were brewed with different wheat varieties of different protein content (8.7–14.4%) and with five different barley malts, varying in degree of modification (soluble protein: 3.9–6.9%). In a first series of experiments, it was investigated whether wheat positively influences the foam stability, a major characteristic of wheat beers. NIBEM and Rudin (CO2) foam analyses revealed that the effect of wheat on foam stability depended on the barley malt used for brewing. When using malt with high foaming potential, wheat exerts a negative influence. However, wheat added to over-modified malt with less foam promoting factors, ameliorates beer foaming characteristics proving that wheat contains foam active compounds. In addition, Rudin (N2) values suggested that wheat positively influences foam stability by decreasing liquid drainage, probably caused by a higher beer viscosity and/or a finer foam bubble size distribution. Furthermore, the haze in wheat beers, which is another important quality characteristic of these beers, was investigated. Permanent haze readings of the 40% wheat beers were lower than 1.5 EBC haze units. For 20% wheat beers, an inverse relation between the permanent haze (9.4–19.3 EBC haze units) and the protein content of the wheat was established. The barley malt used for brewing also influenced permanent haze readings. A positive correlation between the modification degree of the malt and the permanent haze intensity was found. It was concluded that the choice of raw materials for wheat beer brewing considerably influences the visual properties of the beer.