Malting Quality Research Articles

Reduced nitrogen rate sustains malt barley yield and quality in malt barley‐pea rotation

Reduced nitrogen rate sustains malt barley yield and quality in malt barley‐pea rotation

Quality analysis of Norwegian farmhouse malt: A case study

In this case study, we conducted a detailed investigation into the quality of Norwegian farmhouse malt. We analysed the physical, chemical, and organoleptic properties of the malt. Our findings indicate that a specific sample of Norwegian farmhouse malt exhibits a distinct quality, attributed to the production process and the use of a non-malting barley variety with high nitrogen content. The sample of Norwegian farmhouse malt showed low values for all basic malting characteristics. Low values were found especially in cytolytic modification. Additionally, the sensory characteristics of this malt differed significantly from those of conventional, industrially produced malts, especially the smell of the malt and then the smell of the mash after smoke was distinctive.

Multi-response kinetic modelling of the formation of five Strecker aldehydes during kilning of barley malt

Control of aroma formation during production of barley malt is critical to provide consistent and high-quality products for the brewing industry. Malt quality can be affected by the inherent variability of raw material and processing conditions, leading to inconsistent and/or undesirable profiles. Dried green malts were cured isothermally at 65, 78 and 90 °C for 8.4 h, and characteristic aroma compounds (Strecker aldehydes), precursors and intermediate compounds were analysed over time. By kinetic modelling of Strecker aldehydes, based on fundamental chemical pathways, we showed that degradation of Amadori rearrangement products and short-chain dicarbonyls was more sensitive to temperature change due to their higher activation energies compared to other kinetic steps. This study can help maltsters to manipulate formation of Strecker aldehydes, via raw material screening and process control, and hence optimise the organoleptic quality of malts and their products, such as non-alcoholic beers, where these aldehydes play a key role.

Integrative LC-MS and GC-MS metabolic profiling unveils dynamic changes during barley malting

Malting involves complex biochemical transformations affecting sensory and quality attributes. Despite extensive research on storage carbohydrates and proteins in malting, the lack of a detailed metabolic understanding of this process limits our ability to assess and enhance malt quality. This study employed untargeted GC-MS and LC-MS metabolite profiling across six malting timepoints to identify 4980 known metabolites, 82 % of which exhibited significant changes during the malting process. Here we identified stage-dependent metabolic shifts and dynamic chemical classes and pathways between each studied stage. These results can guide the fine-tuning of malting conditions to improve malt quality for beer production and other malt-based applications. Additionally, metabolites with antimicrobial properties were identified, underscoring the interplay between barley and microbial metabolic processes during malting. Further research into these microbial metabolites and cognate microbes may lead to novel malting assessment traits for high-quality and safe malted barley.

Influence of the malting conditions on the modification and variation in the physicochemical properties and volatile composition of barley (Hordeum vulgare L.), rye (Secale cereale L.), and quinoa (Chenopodium quinoa Willd.) malts

The traditional malted cereal used primarily for beverages is barley (Hordeum vulgare L.), while rye (Secale cereale L.) is mainly used in baked goods. In contrast, quinoa (Chenopodium quinoa Willd.) is a gluten-free pseudocereal, rich in starch and high-quality proteins, that can be used similarly to cereals. Their physicochemical properties and volatile compositions (e.g., aroma compounds) directly influence the finished food products. The sharp bitterness of unprocessed rye and the earthy aroma of native quinoa can interfere with the development and acceptance of food products. Malting is known to improve the processing and sensory properties of barley. A face-centered, central composite design was used to investigate the individual and interactive effects of three malting parameters (i.e., steep moisture (SM), germination temperature (T), and germination time (t)) on malt quality indicators (e.g., extract) and volatile formation (e.g., 3-methylbutanal) in rye and quinoa, and were compared to barley. The malt modification predictive models were then used to determine standard malting regimes for brewing quality malts. The malting parameters for the steeping and germination stages were: 43 %, 15 °C, and 6 d for barley; 45 %, 12 °C, and 8 d for rye; and 46 %, 16 °C, 6 d for quinoa. Malt modification and volatile formation were primarily associated with the interactive effect of germination temperature and time. Conversely, steep moisture had limited impact on malt modification but strongly regulated the formation of 34 known (pseudo)cereal volatile compounds. Principal component analysis (PCA) of the volatile data identified (pseudo)cereal specific volatile patterns. Aldehydes were characteristic in the cereal malts, particularly barley, whereas phenyl compounds and pyrazines were abundant in rye and quinoa malts, respectively. Controlling (pseudo)cereal modification and volatile development through the malting process could help deliver targeted sensory properties and improve the acceptance of malt-based food products.

Pulsed electric field treatment applied to barley before malting reduces Fusarium pathogens without compromising the quality of the final malt

The growth of micromycetes and the associated production of mycotoxins during malting represents a potential safety issue and an economic challenge regarding the quality of beer as a product manufactured from malt. The treatment of malted cereals with a pulsed electric field (PEF) may be one method to overcome this issue. In this work were tested PEF conditions that would lead to a reduction in fungal growth without suppressing germination and thus causing deterioration in the technological parameters of the malt. Pre-soaking the grain for more than 3.5 h prior to PEF treatment was found to significantly reduce the germination energy and, compared to the untreated sample, enzymatic activity of the resulting malt. Therefore, a modification consisting of a short pre-soaking (10 min) and PEF treatment (field intensity 3.8 kV/cm, 100 pulses with peak width 20 μs) in a high conductivity environment (0.05 mol/L phosphate buffer) was implemented. This treatment led to a reduction (up to 80%) in growth of some Fusarium species (F. sporotrichoides and F. poae) and the production of corresponding mycotoxins, mainly trichothecenes A and ennianthins. Moreover, the treated malt did not differ significantly from the control malt in terms of enzymatic activity.

Optimum Nitrogen Dose and Malt Quality of Barley Varieties under Saline Water Irrigation

Optimum Nitrogen Dose and Malt Quality of Barley Varieties under Saline Water Irrigation

Phenotyping variability and detecting informative SSR and EST-SSR markers for malt and straw quality characteristics in a diverse panel of wild barley (H. spontaneum) under rainfed and irrigated conditions

Phenotyping variability and detecting informative SSR and EST-SSR markers for malt and straw quality characteristics in a diverse panel of wild barley (H. spontaneum) under rainfed and irrigated conditions

Barley semidwarf allele sdw1.d improves malting quality indirectly in a near isogenic line

AbstractBackground and ObjectivesMalt barley is a specialty crop in which quality characteristics are as important as grain yields. Short stature genes used to increase grain yields in barley have variable effects on malt quality. Effects of sdw1.d semidwarf gene on malting quality were examined using a near isogenic line (NIL) in six field trials.Findingssdw1.d increased malt extract percentage significantly in five trials by 1.7% and decreased test weight (2.0–3.5 kg) in three trials. Grain weight increased in three trials where lodging was common while decreasing in two where lodging was not severe and not changing in one. Diastatic power of sdw1.d NIL was significantly higher in four trials and similar in two trials compared to recurrent parent Tokak. No change was observed for α‐amylase activity.ConclusionsThe lack of reports indicating a direct association of Sdw1 mutants with diastatic power and the presence of quantitative trait locus (QTL) around the Sdw1 gene in numerous studies implied that higher diastatic power of the NIL could be due to linkage rather than the pleiotropic effect of sdw1.d.Significance and NoveltyImproved malting quality of the NIL appeared to be the result of indirect effects of sdw1.d due to reduced lodging and linkage with diastatic power QTL.

Response of Malt Barley (<i>Hordeum distichum L.</i>) to Different Phosphorus Fertilizer Rates and Irrigation Levels Under Furrow Irrigation Methods in South Eastern Ethiopia

Nutrient availability to crops is a function of soil type, moisture condition, environment, crop type, and management and their interaction affects nutrient use efficiencies and crop growth conditions. The objective of this study was to determine the optimum P rate and deficit irrigation level, as well as to identify the interactive effect of nutrient and moisture levels on yield and yield quality malt barley under irrigation in Ormiya region Tiyo district. The experiment was conducted at small plot level for three consecutive years from 2020/21 to 2022/23 G.C. This experiment was conducted at Kulumsa Agricultural Research Center On-Station arranged by split-plot layout with RCBD design by three replications. Irrigation amounts (100%, 75% and 50%) were assigned the main plot and phosphorus fertilizer rates (0, 10, 20, 30 and 40 kg) corresponded to the subplot. The combined effect of irrigation levels and phosphorus fertilizer rate had a significant effect (p < 0.05) on malt barely grain yield, above-ground biomass, thousand kernel weight and water productivity but not on plant height, seeds per spike and protein content. The highest grain yield and above-ground biomass were 3.16 t/ha and 6.77 t/ha obtained from the application of 100% ETc with 30 kg of phosphorus fertilizer. The maximum water productivity (0.97 kg/m<sup>3</sup>) was observeat the application of 75% ETc with 30 kg of Phosphorus fertilizer while more profitable practice was found at 100% ETc with 30 kg of phosphorus application. The highest protein content (15.57%) was observed at the application of 50% deficit irrigation and the lowest (14.66%) was observed at 100% ETc irrigation application. Applying the optimum amount of irrigation with 30 Kg phosphorus fertilizer gives high grain and above biomass yield and is economically profitable in Tiyo district and agroecologies similar to Tiyo.

The effect of L-cysteine on starch and protein degradation during barley germination.

In order to investigate the impact of L-cysteine (L-Cys) on starch and protein degradation during barley germination. The amylase activities, degradation of macromolecules during germination were determined in this study. Barley was germinated in petri dish for 0 to 5days with different levels of L-Cys (0mM, 2.5mM, 5mM, 10mM). L-Cys addition increased the total limit dextrinase (LD) activities and decreased the LD inhibitor activities during whole germination stage. The activities of α-amylase, β-amylase and free LD were increased with the addition of 2.5, 5mM L-Cys at germination days 1 to 4. Due to higher amylase in malt with the addition of L-Cys, the non-fermentable sugars were reduced and the glucose, maltotriose were improved. Furthermore, the protein degradation analysis showed that low molecular weight protein increased and middle molecular weight protein decreased obviously in wort from the malt germinated with L-Cys, demonstrating that the L-Cys promote the protein degradation. Lastly, the filtration performance of malt with the addition of L-Cys during malting was better than the control. In conclusion, L-Cys can promote the degradation of storage material (starch, protein) during barley germination, leading to a better green malt quality.

Barley varieties registered in the Czech Republic after the harvest of 2023

After the 2023 harvest, four varieties of spring barley were registered in the Czech Republic. The malting quality was determined in three varieties. After four years of testing, LG Tuplak was registered. After three years of testing, the spring barley varieties LG Lokal, Sting, and the non-malting variety Ranee were registered. LG Tuplak and LG Lokal showed low activity of proteolytic and cytolytic enzymes and a low level of apparent final attenuation and thus fulfilled the conditionsfor varieties recommended for the production of beer with the protected geographical indication 'České pivo'. The spring barley variety Sting showed very good malting quality. It provided a sweet wort with a rich extract content in malt dry matter (above 83%). Proteolytic modification was optimal to higher in this variety. Cell wall degradation was at an optimal level in the Sting variety. The varieties tested gave clear to opalescent sweet wort.

Registration of ‘UC‐Alameda’, a California adapted, non‐glycosidic nitrile‐producer, two‐row spring malting barley

AbstractThe emerging malting industry in California needs adapted cultivars for a sustainable local barley production. ‘UC‐Alameda’ (Reg. no. CV‐381, PVP 202300263, PI 701932) is a two‐row, spring malting barley (Hordeum vulgare L.) released by the University of California, Davis, Agricultural Experiment Station, in 2022. UC‐Alameda is a highly productive cultivar with satisfactory malting quality for local craft maltsters. UC‐Alameda is adapted to the California Central Valley (Sacramento and San Joaquin Valleys) and is resistant to the most common diseases present in this region (e.g., Barley yellow dwarf virus, Cereal yellow dwarf virus, stripe rust, and powdery mildew) and moderately resistant to scald and net blotch. It was evaluated in preliminary trials, as B9K62, from 2017 to 2023 at Davis, CA, and by the University of California Regional Small Grains Testing program, as UC1911, from 2018 to 2023 for late fall planting in the Central Valley. UC‐Alameda is a non‐glycosidic nitrile producer, which is an important trait for craft‐maltsters and distillers. UC‐Alameda satisfies the quality criteria of the local craft malting and brewing industry interested in sourcing locally grown malting barley.

Enhancing barley yield potential and germination rate: gene editing of HvGA20ox2 and discovery of novel allele sdw1.ZU9.

Several dwarf and semi-dwarf genes have been identified in barley. However, only a limited number have been effectively utilized in breeding programs to cultivate lodging resistant varieties. This is due to the common association of dwarf and semi-dwarf traits with negative effects on malt quality. In this study, we employed gene editing to generate three new haplotypes of sdw1/denso candidate gene gibberellin (GA) 20-oxidase2 (GA20ox2). These haplotypes induced a dwarfing phenotype and enhancing yield potential, and promoting seed dormancy, thereby reducing pre-harvest sprouting. Moreover, β-amylase activity in the grains of the mutant lines was significantly increased, which is beneficial for malt quality. The haplotype analysis revealed significant genetic divergence of this gene during barley domestication and selection. A novel allele (sdw1.ZU9), containing a 96-bp fragment in the promoter region of HvGA20ox2, was discovered and primarily observed in East Asian and Russian barley varieties. The 96-bp fragment was associated with lower gene expression, leading to lower plant height but higher germination rate. In conclusion, HvGA20ox2 can be potentially used to develop semi-dwarf barley cultivars with high yield and improved malt quality.

Metagenomic sequencing and reconstruction of 82 microbial genomes from barley seed communities

Barley (Hordeum vulgare) is essential to global food systems and the brewing industry. Its physiological traits and microbial communities determine malt quality. Although microbes influence barley from seed health to fermentation, there is a gap in metagenomic insights during seed storage. Crucially, elucidating the changes in microbial composition associated with barley seeds is imperative for understanding how these fluctuations can impact seed health and ultimately, influence both agricultural yield and quality of barley-derived products. Whole metagenomes were sequenced from eight barley seed samples obtained at different storage time points from harvest to nine months. After binning, 82 metagenome-assembled genomes (MAGs) belonging to 26 distinct bacterial genera were assembled, with a substantial proportion of potential novel species. Most of our MAG dataset (61%) showed over 90% genome completeness. This pioneering barley seed microbial genome retrieval provides insights into species diversity and structure, laying the groundwork for understanding barley seed microbiome interactions at the genome level.

Genome-wide association study on seed dormancy in barley

Abstract Seed dormancy is an important trait associated with pre-sprouting and malting quality in barley. Genome-wide association studies (GWASs) have been used to detect quantitative trait loci (QTLs) underlying complex traits in major crops. In the present study, we collected 295 barley (Hordeum vulgare L.) accessions from Australia, Europe, Canada and China. A total of 25,179 single nucleotide polymorphism (SNP)/diversity arrays technology sequence markers were used for population structure, linkage disequilibrium and GWAS analysis. Candidate genes within QTL regions were investigated, and their expression levels were analysed using RNAseq data. Five QTLs for seed dormancy were identified. One QTL was mapped on chromosome 1H, and one QTL was mapped on chromosome 4H, while three QTLs were located on chromosome 5H. This is the first report of a QTL on the short arm of chromosome 5H in barley. Molecular markers linked to the QTL can be used for marker-assisted selection in barley breeding programmes.

Emerging approaches to improve barley malt processing and quality: Ultrasound-assisted hydration and ethanol pre-treatment to drying

This work aimed to evaluate how two emerging technologies impact the malting process and the quality of barley malt: ultrasound-assisted hydration and ethanol pre-treatment to drying. All three steps of malting (hydration, germination, and drying), as well as the resulting malt's quality indicators, were evaluated. Conventional and ultrasound-assisted (25 kHz; 91 W/L, 20 °C) hydration were carried out, followed by germination, ethanol (99.5%) pre-treatment (immersion 30 min, 25 °C), and convective drying (50 °C, 1 m/s). Texture analysis demonstrated that the different stages of the malting process modify the structure and composition by increasing or decreasing the compression force in the grain. The ultrasound-assisted hydration improved the second hydration stage, where hydration resistances were greater, reducing hydration time by 38%; moreover, ultrasound accelerated the germination step with root growth 1.17 times greater. During drying, ultrasound-assisted hydration followed by ethanol pre-treatment, reduced drying time by 38.5% (barley) and 17.8% (malt). Both evaluated technologies, therefore, intensify the malting process. In addition, it was demonstrated that their use increased the alpha (9%) and beta-amylase (7%) activity in malt and modified paste and gel-forming properties of barley and malt flours. Therefore, these results suggest that the use of ultrasound improved hydration and germination processes, and ethanol pre-treatment accelerated the drying process because of improved mass transfer, both without negative impact on malt quality.

Barley varieties registered in the Slovak Republic after the harvest of 2023

After the harvest 2023, three varieties were registered in the Slovak Republic after three years of testing: the spring barley variety LG Rhapsody, the two-row winter barley variety Claudia, and the six-row winter barley variety MH Irén. The malting quality was determined for the varieties LG Rhapsody and Claudia. LG Rhapsody gave extract in malt dry matter of 83.2%. Proteolytic modification of this variety was high (Kolbach index 52.3%). The diastatic power (343 WK), the quality of the sweet wort (apparent final attenuation 82.1%), and the cytolytic modification (friability 94% and β-glucan content 60 mg/l) were at an optimal level. In all cases, the variety gave a clear sweet wort. The winter two-row barley variety Claudia gave a sweet wort with an extract of 81.5%. Kolbach index (46.2%) and diastatic power (508 WK) were at optimal levels. The quality of the sweet wort (apparent final attenuation 80.5%) and the cytolytic modification (friability 83% and β-glucan content of the wort 169 mg/l) were at an average level.

Malting and Brewing Performance of β-Amylase-Deficient Barley

β-Amylase (α-1,4-glucan maltohydrolase; EC 3.2.1.2) is known to be an important enzyme in beer brewing. To identify the contribution of β-amylase in more detail, two β-amylase-deficient barley, ‘Backcrossed line (BCL)-Haruna’ and ‘Nittakei 81’, were used for the investigation of malt quality and brewing characteristics. ‘BCL-Haruna’ was bred by the backcross method for the introduction of the β-amylase-deficient trait from landrace barley (‘Tibet Violet 1’) to Japanese traditional malting barley ‘Haruna Nijo’. ‘Nittakei 81’ was bred by crossing between Japanese malting barley ‘Sukai Golden’ and ‘Tibet Violet 1’. With regards to the malting quality under 41.0% target cast moisture in micro-malting, the diastatic power (DP) and apparent attenuation limit (AAL) of ‘BCL-Haruna’ and ‘Nittakei 81’ were 408 oWK and 416 oWK and 12.4% and 14.8% lower than those of the control variety ‘Haruna Nijo’. Oligosaccharide analysis indicated that the maltose concentration of the ‘Nittakei 81’ wort was 19.7 g/L lower in comparison to a standard European malting barley ‘Propino’ wort, although the maltotetraose and maltopentaose concentrations of the ‘Nittakei 81’ wort were 5.6 g/L and 2.7 g/L higher than those of the ‘Propino’ wort. After fermentation, the alcohol concentration of the ‘Nittakei 81’ beer was 0.67% lower compared with the ‘Propino’ beer, and the extract and concentrations of maltotetraose and maltopentaose of the ‘Nittakei 81’ beer were 5.0 g/L and 2.5 g/L higher than those of the ‘Propino’ beer. The results indicate that the β-amylase-deficient barley has a unique malting quality, especially lower DP and AAL, which might induce inadequate starch degradation or fermentation. However, this trait caused no serious issues during the brewing process, suggesting the possibility of β-amylase-deficient barley as a unique brewing material including low-alcoholic and non-alcoholic beer production with a specific saccharide composition.

Registration of ‘Top Shelf’ barley: The first glycosidic nitrile‐null, winter malting cultivar to be released in North America

Abstract‘Top Shelf’ (Reg. no. CV‐380, PI 704478), experimental designation DH162310, is a two‐row winter barley (Hordeum vulgare L.) released by Oregon Agricultural Experiment Station in 2023. It is a malting cultivar that is known to be a non‐producer of glycosidic nitrile (GN0). GN0 is the precursor to a regulated compound (ethyl carbamate) in distilled spirits and thus, the GN0 trait is becoming a requisite for malting cultivars geared toward distilling. While GN0 spring cultivars have been available for over 20 years, Top Shelf is the first winter GN0 cultivar to be released in North America, and only the second globally. In addition to its GN0 status it exceeds contemporary agronomic and malt quality expectations. Over 5 years of field trials in Oregon it performed equal to or better than the check entries. It shows high yields, plump grains, and test weights. It also has good resistance to scald (caused by Rhynchosporium commune) and preliminary data suggest resistance to barley stripe rust (Puccinia striiformis f. sp. hordei). Results were confirmed in field trials in southern Idaho, a major malting barley production region, and a target environment for this cultivar. Under standard malting protocols Top Shelf meets the guidelines for malt and all‐malt and/or grain distilling, and has high extract, enzymatic activity, and free amino nitrogen. When malted under optimized conditions, mimicking commercial distilling malt production, it produced even better results. As one of only a handful of GN0 cultivars available in the United States with potential for mainstream production, Top Shelf provides an important option for the distilling supply chain.