Composition and hardness of malting red and white kaffir sorghum [Sorghum bicolor (L.) Moench] dried under the sun.

This investigation determined how changes in chemical composition of malting red and white kaffir sorghum grains dried under the sun affected the resistance of the malts to fracture as determined by the Monsanto Hardness Tester. The sorghum grains were malted by a modification of the 2-step wet steep method and dried under the sun. The results showed that malting increased diastatic activity to peak values of 78.40°L and 56°L in the red and white malts; moisture content from 115 to 165 g/kg and 125 to 170 g/kg, crude protein from 104.20 to 183 g/kg and 92.8 to 153.20 g/kg respectively but decreased the fat content. Grain hardness decreased from 83.20 to 42.50 N in the red malts and from 72.70 to 39.30 N in the white. The increases in diastatic activity, moisture, crude protein and reduced fat contents appear to have contributed most to the reduction in grain hardness.

Assessment of malting characteristics of different Indian barley cultivars.

The impact of malting on composition and malt quality parameters such as diastatic power, α-amylase activity, ß-amylase activity, hot water extract and ß-glucan content were investigated in five different Indian barley cultivars. Protein content of grains increased significantly after malting. Soluble protein content of unmalted grain, which ranged from 3.20-3.93% increased after malting to 4.26-4.85%. Diastatic power of mature grain varied across genotype and their level increased (58.98-81.05 to 115.93-142.45 DP°) after malting. Diastatic power correlated very strongly with protein content (r = 0.90) and strongly with ß-amylase activity (r = 0.74). α-amylase, which was low (0.042-0.189 Ceralpha Unit/g) initially in unmalted grain, was synthesized during germination to the range of 149.42-223.78 Ceralpha Unit/g. The correlation between diastatic power and α-amylase was very weak (r = - 0.04). The levels of ß-amylase in unmalted grain was in the range of 13.97-18.26; that amount got reduced after malting to 12.55-15.97 Betamyl-3 U/g. ß-amylase had a strong positive correlation (r = 0.85) with grain protein. Malted grain which had higher protein content showed very strong negative correlation (r = - 0.86) with hot water extract value. ß-glucan content reduced 70-80% from the initial level, across genotypes.

Characterization of a near isogenic barley line with high grain ß-amylase activity reveals a separation in the tight co-regulation of B-hordeins (Hor2) with endosperm-specific ß-amylase (Bmy1).

GSHO 2096 is a near isogenic barley line with extremely high grain ß-amylase activity, a desirable trait in the malting and brewing industry. High levels of grain ß-amylase activity are caused by a surge in endosperm-specific ß-amylase (Bmy1) gene expression during the early stages of grain development with high expression levels persisting throughout development. Origins of the high ß-amylase activity trait are perplexing considering GSHO 2096 is not supposed to have grain ß-amylase activity. GSHO 2096 is reported to be derived from a Bowman x Risø 1508 cross followed by recurrent backcrossing to Bowman (BC5). Risø 1508 carries a mutated form of the barley prolamin binding factor, which is responsible for Bmy1 expression during grain development. Thus, the pedigree of GSHO 2096 was explored to determine the potential origins of the high grain ß-amylase trait. Genotyping using the barley 50k iSelect SNP array revealed Bowman and GSHO 2096 were very similar (95.4 %) and provided evidence that both Risø 56 and 1508 are in the pedigree. Risø mutants 56 and 1508 both have perturbed hordein gene expression leading to a discernable pattern using SDS-PAGE. GSHO 2096 and Risø 56 have the same hordein pattern whereas Bowman and Risø 1508 have unique patterns. RNAseq revealed that Hor2 (B-hordein) gene expression was completely downregulated making it unique as the only known line with Bmy1 expression without Hor2 co-expression. Regardless of pedigree, GSHO 2096 remains an extremely valuable high ß-amylase activity line with potential utilization in breeding for malt quality.

Barley yield and malt quality affected by fall and spring planting under rainfed conditions.

Background: As a result of the changing climate characteristics, it is necessary to reevaluate the planting time for crop plants. The aim of the present study was to determine the quality characteristics of malting barley cultivars in fall and spring plantings. Methods: Sixteen malting barley cultivars were used. Two fall-planted and two spring-planted trials were conducted in two consecutive years. The field trials were carried out in a randomized complete block design with four replications in Tokat province of Turkey under rainfed conditions. Results: Grain yields varied between 4.38 and 5.71 t/ha in fall-planted trials and between 3.12 and 4.89 t/ha in spring-planted trials. Malt extracts were between 77.0% and 78.0% kg in fall-planted trials and between 73.9% and 76.9% in spring-planted trials. Alpha amylase activities ranged from 77.9 to 81.4 Ceralpha unit (CU)/g in fall-planted trials and from 80.8 to 100.9 CU/g in spring-planted trials. Diastatic power ranged from 194.5 to 331.1 Windisch-Kolbach unit (°WK) in fall-planted trials and from 129.0 to 259.8 °WK in spring-planted trials. GGE biplot analysis indicated that winter barley cultivar Durusu and facultative barley cultivar Ince-04 were the best with consistent grain yields while Ince-04 was the best with stable malt extract across the trials. In scatter plot graphics, winter barley cultivars Durusu, Aydanhanim, Yildiz and facultative Ince-04 had superior performance in fall-plantings for grain yield and malt extract. In spring planting, facultative Ince-04 had higher performance than those of other cultivars. In spring plantings, facultative or winter barley cultivars that do not have strong vernalization requirement had better yield and malt quality. Appropriate planting time and cultivars can allow a better use of available water in malt barley production under rainfed conditions. Lastly, instead of evaluating the grain yield or malt quality alone, it would be best to evaluate the target product (malt extract percentage) obtained from a particular region, process, or production methodology.

Malting quality of seven genotypes of barley grown in Nepal.

There has been very limited work on the malting quality of barley grown in Nepal. This work used completely randomized experiment for seven barley genotypes, namely Xveola-45, Coll#112-114/Muktinath, Xveola-38, Solu uwa, NB-1003/37-1038, NB-1003/37-1034, and Bonus, collected from Hill Crop Research Program (Dolakha, Nepal) to study the effect of genotypes on the chemical composition and functional properties of barley and malt. Barley was steeped for 24 hr followed by 72 hr germination in room temperature (25 ± 3°C). Germinated barley was dried (45°C/6 hr, 50°C/4 hr, 55°C/8 hr, 70°C/1 hr, 80°C/3 hr) in a cabinet drier. Multistage dried barley was then ground to pass through a 250 µm screen. Among the chemical composition, protein and reducing sugar were affected by genotype (p < .05) in barley except for ß-glucan. Functional properties, particularly bulk density, water absorption capacity, oil absorption capacity, and viscosity, were affected by genotype (p < .05) in barley, whereas except for density, all the parameters were different (p < .05) for malt. The highest diastatic power among all genotypes was recorded for solu uwa (329.25 ºDP) followed by Muktinath (271.15 ºDP). There was no significant change (p < .05) in a protein of all genotypes after malting, whereas ß-glucan and viscosity significantly decreased (p < .05) for all genotypes after malting. The remaining parameters for all genotypes were not affected (p < .05) by malting. Solu uwa had higher enzymatic activity, whereas Xveola-38 and Muktinath were found to be better for complimentary food preparation.

Comparative gene expression analysis of the ß-amylase and hordein gene families in the developing barley grain.

Expression of hordeins and ß-amylase during barley grain development is important in determining malting quality parameters that are controlled by protein and malt enzyme levels. The relationship between protein and enzyme levels is confounding because, in general, protein and malt enzyme activity are positively correlated and the malting and brewing industries demand relatively low levels of protein and relatively high levels of enzymes. Separation of these traits is desirable because high protein levels are one of the primary causes of barley not meeting malt quality standards. Studies on barley grain development have not resulted in a consensus on the temporal accumulation of hordein and endosperm-specific ß-amylase (Bmy1) and thus, it is unclear whether hordeins and Bmy1 are under control of the same temporal regulator (s). Therefore, temporal expression patterns of hordeins (B- [Hor2], C- [Hor1], D- [Hor3], and γ-hordein [Hor5]) were compared to Bmy1 throughout grain development (5 to 35 days after anthesis (DAA)). Transcript accumulation between hordeins and Bmy1 occurred simultaneously beginning during the pre-storage phase of grain development whereas the B1-hordein protein appeared two days before Bmy1 most likely due to variations in gene copy number. Interestingly, the largest increase in hordein and Bmy1 transcript levels occurred between 5 and 9 (Hor2, Hor2-B1, Hor2-B3, Hor3, Hor5-γ1, and Hor5-γ3) or 9 and 13 DAA (Hor1 and Bmy1). Additionally, ubiquitous ß-amylase (Bmy2) has a novel expression pattern and was the predominant ß-amylase present between 5 and 15 DAA whereas Bmy1 was the predominant ß-amylase present between 17 and 35 DAA.

Association Mapping of Diastatic Power in UK Winter and Spring Barley by Exome Sequencing of Phenotypically Contrasting Variety Sets.

Diastatic Power (DP) is an important quality trait for malt used in adjunct brewing and distilling. Substantial genetic variation for DP exists within UK elite barley cultivars, but breeding progress has been slow due to the limited demand, compared to the overall barley market, and difficulties in assessing DP. Estimates of DP (taken from recommended and national list trials between 1994 and 2012) from a collection of UK elite winter and spring varieties were used to identify contrasting sets of high and low DP varieties. DNA samples were pooled within sets and exome capture sequencing performed. Allele frequency estimates of Single Nucleotide Polymorphisms (SNPs) identified from the sequencing were used to identify genomic locations associated with differences in DP. Individual genotypes were generated from a set of custom KASP assays, both within sets and in a wider germplasm collection, to validate allele frequency estimates and marker associations with DP. QTL identified regions previously linked to variation in DP as well as novel associations. QTL colocalised with a number of genes annotated as having a diastase related function. Results indicate that winter barley is more genetically diverse for genes influencing DP. The marker assays produced by this work represent a resource that is available for immediate use by barley breeders in the production of new high DP varieties.

Comparative proteomic analysis of Dan'er malts produced from distinct malting processes by two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE).

The malting process is the controlled germination, followed by drying, of the barley grain. For brewing beer, the malting process is modified according to the features of the barley variety being malted. In China, there are two schedules routinely used for malting the widely grown Dan'er cultivar, processes I and II. The quality of malt produced with process II is considered to be superior to that from process I for Dan'er by maltsters and brewers. In the present study, comparative proteomic analysis was performed between Dan'er malts produced by malting processes I and II. The data showed that enzymes and proteins responsible for cell wall polysaccharide degradation and starch and protein hydrolysis were more abundant in malt produced by process II, leading to improved quality, especially for the commercially important filterability, saccharification time, and diastatic power (DP) quality traits. In addition, to verify the proteomic results, the activities of several key enzymes (α-amylase, ß-amylase, and limit dextrinase) were compared between the two malts. This enabled the influence of malting process on malt quality to be determined and suggested malting process schedule changes to optimize the malting process for the Dan'er cultivar, especially for improving filterability, which is often deemed as suboptimal by maltsters and brewers.