Effects of Grain and Malt â‐Glucan on Distilling Quality in a Population of Hull‐less Barley

A population of barley lines, derived by mutation in the hull‐less variety, Penthouse, was included in a replicated trial, along with Penthouse and the hulled malting cultivar, Optic. Samples were assessed for a range of grain quality traits, then malted, with germination for either 4 or 5 days, prior to kilning. Most lines had grain β‐glucan contents lower than that of Penthouse, but there was no significant correlation between grain and malt β‐glucan content. Malt β‐glucan levels were indicative of differences in cell wall breakdown between 4 and 5 days germination, but negative associations with distilling parameters Extract and Alcohol Yield, were not statistically significant. It was concluded that the lines differed in the rate and extent of cell wall breakdown and that grain shape may influence modification in distal parts of the grain. However, a malting regime, optimised to suit Optic may be less suited to discriminating between hull‐less lines of reasonable quality.     

Effects of malting on β‐glucanase and phytase activity in barley grain

The effects of malting on β‐glucan and phytate were investigated in one naked and one covered barley by a full factorial experiment with three factors (steeping temperature, moisture content and germination temperature) each with two levels. Analysis of total content of β‐glucan in the malted samples showed small changes after steeping at the high temperature (48 °C), while steeping at the lower temperature (15 °C) gave a significantly lower content. This trend was even stronger for β‐glucan unextractable at 38 °C. Analysis of the activity of β‐glucanase for the samples steeped at 15 °C showed a strong increase over the time of germination, while those steeped at 48 °C had a much slower development. The other two factors influenced the outcome to a small extent, mainly because the steeping temperature was the most important factor overall where any changes in β‐glucan and β‐glucanase were observed. When β‐glucan was extracted at 100 °C, a larger yield was obtained, and this was influenced by the steeping temperature in a much stronger way than for β‐glucan extracted at 38 °C. Determination of average molecular weight for β‐glucan extracted at 100 °C gave a lower value for samples steeped at 15 than at 48 °C. The design did not have any large effects on phytate degradation and phytase activity. However, it indicated that selective control of the enzymes might be possible, since phytase activity was barely affected by the parameters studied, while β‐glucanase was heavily affected. © 2002 Society of Chemical Industry     

Phytate content is reduced and β‐glucanase activity suppressed in malted barley steeped with lactic acid at high temperature

The effect of different steeping conditions on phytate, β‐glucan and vitamin E in barley during malting was studied by a full factorial experiment with three variables (steeping temperature, barley variety and steeping additions). Addition of lactic acid to the steeping water induced a reduction of phytate during steeping and germination, especially in combination with the high steeping temperature (48 °C). Furthermore, lactic acid and high temperature steeping inhibited β‐glucanase development, resulting in a well‐preserved β‐glucan content after germination. When steeping was conducted without addition of lactic acid, the low steeping temperature (15 °C) promoted development of both phytase and β‐glucanase activity during germination. A slightly higher level of tocopherols and tocotrienols was observed in samples steeped at 15 °C than in samples steeped at 48 °C. However, addition of lactic acid reduced the amount for both temperatures. When lactic acid bacteria were added to the steeping water none of the parameters studied differed from samples steeped with water only. The results show the possibility of combining phytate degradation with a preserved β‐glucan content during malting and can thus be of interest for development of cereal products with improved nutritional value. Copyright © 2004 Society of Chemical Industry     

The enrichment of Asian noodles with fiber‐rich fractions derived from roller milling of hull‐less barley

Fiber‐rich fractions (FRF) derived from roller milling of waxy (W) and high amylose (HA) starch hull‐less barley genotypes were evaluated for suitability as functional ingredients in fresh and dried white salted (WSN) and fresh yellow alkaline (YAN) noodles. FRF‐W and FRF‐HA both contained over 300 g kg⁻¹ dietary fiber, and over 200 g kg⁻¹ of β‐glucans. Replacement of 250 g kg⁻¹ Canada Prairie Spring White (cv AC Vista) wheat patent flour with the FRF posed no problems in noodle processing, although water absorption had to be substantially increased. All three noodle types enriched with the FRF were significantly darker and contained more brown specks than the wheat flour control noodles. The presence of the FRF reduced cooking time of fresh YAN and WSN by ∼50%. The addition of FRF improved cooked YAN texture, as evidenced by increased firmness and resistance to compression. FRF‐enriched fresh WSN were comparable to the wheat flour control noodles for those parameters, whereas enrichment of dry WSN by FRF imparted less firmness and less chewiness. FRF‐enriched fresh YAN and WSN offer consumer convenience due to shorter cooking time, improved nutritional quality and acceptable cooking quality. These features might make FRF‐enriched noodles sufficiently attractive to health‐conscious consumers to overcome the negative effects of color and appearance Copyright © 2005 Society of Chemical Industry     

Physicochemical and structural characteristics of starches from Chinese hull‐less barley cultivars

Fourteen hull‐less barley cultivars, collected from four major cultivated areas in China, were employed to investigate the structural and physicochemical properties of their starches in this study. Relatively wide variations in physicochemical properties of the starches were observed. Amylose content ranged from 23.1% to 30.0%, swelling power and water solubility index ranged from 12.8 to 19.9 g g^?1 and 12.7% to 23.7% respectively. Peak viscosity was from 170 to 346 Rapid Visco Unit (RVU), peak temperature (T_p) of starch gelatinisation was from 55.6 to 61.8 °C and enthalpy of starch retrogradation ranged from 0.3 to 3.1 J g^?1. Weight‐based chain‐length proportions of fa, fb₁, fb₂ and fb₃ in amylopectins ranged from 21.65% to 24.95%, 44.48% to 49.44%, 15.56% to 17.19% and 9.83% to 16.66% respectively. Correlation analyses showed that amylose content was inversely related to pasting parameters and enthalpy of gelatinisation. Pasting properties and amylopectin structures were the most important parameters to differentiate starch properties among different hull‐less barley cultivars in this study. This work will be useful for exploring applications of Chinese hull‐less barley starches in food and non‐food industries.     

Variety and germination time effect on total β‐glucan,water‐insoluble β‐glucan,water‐soluble β‐glucan components and β‐glucanase levels in improved sorghum varieties SK5912, KSV8 and ICSV400 before and after malting and their relationships to wort viscosity

The effects of variety and germination time on β‐glucan components – total β‐glucan (TBG), water insoluble β‐glucan (WIBG) and water soluble β‐glucan (WSBG) and β‐glucanase (BG) levels – before and after malting in improved sorghum varieties SK5912, KSV8 and ICSV400 and their relationships to wort specific viscosity (SV) were studied. This study was part of efforts to aid local malting and brewing industries in the application of sorghum varieties that are abundantly available to reduce costs. At the fifth day of germination, variety ICSV400 had the lowest TBG, WIBG and WSBG levels in its raw and malt samples. Variety SK5912 had the highest TBG, WIBG and WSBG levels in its raw samples, while variety KSV8 had the highest levels of TBG, WIBG and WSBG in its malt samples. Similarly, variety ICSV400 malts developed the highest BG levels, while the KSV8 malts gave the lowest level. The effect of variety, germination time and variety × germination time interaction was significant (p < 0.05) on the TBG, WIBG and BG levels and was not significant on the WSBG levels. Weak and significant correlation of TBG levels with SV (0.25, p < 0.05 for SK5912; 0.24, p < 0.05 for KSV8; and 0.31, p < 0.05 for ICSV400) was observed in all the samples, suggesting that the low β‐glucan levels may not be primarily and solely responsible for any viscosity impediments associated with sorghum worts during run‐off. With improvement in the effective utilization of sorghum, ICSV400 appeared the most suitable variety for malting and brewing in Nigeria.Copyright © 2016 The Institute of Brewing & Distilling     

A predictive model of the effects of genotypic,pre‐ and postharvest stages on barley β‐glucan levels

BACKGROUND: β‐Glucan is a bioactive component of cereal grains that has many potential uses and health‐promoting benefits. Recent research has focused on improving the nutritional value of food by increasing human exposure to β‐glucan. This study looks at the development of a farm‐level baseline model (including scenario analysis) to evaluate the impact of pre‐ and postharvest stages (including genotypic factors, environmental conditions, agronomic factors and storage) on β‐glucan levels in barley. Monte Carlo simulation techniques were employed to model various stages in pre‐ and postharvest processes and to simulate the factors influencing the level of β‐glucan content in both hulled barley (H_B) and hull‐less barley (H_LB) genotypes. RESULTS: The baseline model found that the mean simulated level of β‐glucan was 40.99 and 56.77 g kg^?1 for H_B and H_LB genotypes respectively. A sensitivity analysis highlighted that genotype was the most important parameter in determining the final β‐glucan content (correlation coefficients of 0.66 and 0.78 for H_B and H_LB respectively), more so than any of the agronomic factors analysed. The scenario analysis highlighted the importance of harvest date (scenario 2) and storage conditions (scenario 3), with a potential 32.6 and 32.7% decrease in β‐glucan (compared with the baseline model) if harvesting is carried out early during physiological maturity (i.e. at growth stage 92) and a potential 20.1 and 19.5% increase in β‐glucan for H_B and H_LB respectively if storage time is minimised. CONCLUSION: This study predicted the influence of genotypic, pre‐ and postharvest operations on β‐glucan content and thus allows strategies to be identified to influence β‐glucan content in barley products. Copyright © 2008 Society of Chemical Industry     

Changes in β-glucan and other carbohydrate components of barley during malting

Changes in total (1→3), (1→4)-β-glucan content were followed during the micro-malting of nine varieties of barley with a wide range of malting qualities. These changes were related to estimates of endosperm modification based upon staining with Calcofluor. β-Glucan content declined from an average of 3.54% in the barley to 0.75% in the malt. Pentosan and total starch (including starch-derived oligosaccharides) levels showed comparatively little change during malting. β-Glucan composition of the barley was a poor indicator of malting performance. However, the β-glucan, starch and xylose contents of the malt all showed significant correlations with malt extract. Estimation of malt β-glucan content gave the best indication of malt quality. Direct determination of β-glucan may be of more value in assessing malt quality than indirect techniques based upon assessing modification of stained grains.     

Breeding of lipoxygenase‐1‐less malting barley variety ‘Satuiku 2 go’

The lipoxygenase‐1‐less (LOX‐less) trait has positive effects on beer quality, in particular, improvement of flavour stability related to the reduction of beer‐deteriorating substances such as trans‐2‐nonenal. ‘Ryohfu’ is the only spring‐sown malting barley variety grown in Hokkaido, located in the northern part of Japan, and has been used in the Japanese brewing industry for over 20 years. ‘Satuiku 2 go’ was developed as the first LOX‐less malting barley variety in Japan by successive back‐crossing with molecular marker‐assisted selection to introduce the LOX‐less trait into the recurrent parent ‘Ryohfu’. The agronomic performance and general malt quality of ‘Satuiku 2 go’ were almost equivalent to those of ‘Ryohfu’. Wort and beer analyses at the pilot‐scale brewing trial indicated that the LOX‐less trait had little effect on the general characteristics. In contrast, the beers made from ‘Satuiku 2 go’ malt exhibited reduced levels of trans‐2‐nonenal and trihydroxyoctadecenoic acid. The sensory evaluation demonstrated the superiority of ‘Satuiku 2 go’ beers stored under differing conditions in terms of staleness. It can be concluded that the LOX‐less trait was effective in different genetic backgrounds of the recurrent parents used for the development of LOX‐less malting barley varieties. Copyright © 2018 The Institute of Brewing & Distilling     

Malting Performance of Normal Huskless and Acid‐Dehusked Barley Samples

Sulphuric acid dehusked barley had a higher germinative energy and lower microbial infection than normal huskless (naked) barley, suggesting that the pericarp layer harboured microbial infection which may have limited the germination rate. Dehusking the normal huskless barley using sulphuric acid resulted in lower microbial infection, and increased germinative energy. The normal huskless barley sample had a higher β‐glucan content than the acid‐dehusked barley and had slower β‐glucan breakdown during malting. This resulted in the release of seven times more β‐glucan during mashing, and the production of wort of higher viscosity. The normal huskless barley sample had a higher total nitrogen content than the acid‐dehusked barley but both samples produced similar levels of amylolytic (α‐ and β‐amylase) activity over the same malting period. No direct correlation was found between barley total nitrogen level and the amylolytic activity of the malt. When barley loses its husk at harvest, the embryo is exposed and may be damaged. This may result in uneven germination which can reduce malting performance and hence malt quality.     

Potential of Hull‐less Barley Malt for Use in Malt and Grain Whisky Production

Hull‐less (or husk‐less) barley is possibly one of the most important developments in barley in recent years. This study looked at the potential of hull‐less barley for use by the Scotch whisky industry. By modifying the malting conditions for hull‐less barley, it was possible to provide good alcohol yield as well as significant improvements in processing characteristics. The biochemistry controlling the germination of hull‐less barley was consistent with established knowledge about ‘normal’ hulled barley except that care is needed to ensure the consistency of feedstock, particularly since hull‐less barley may be prone to embryo damage during harvesting in the field. Our results indicated that the new batches of hull‐less barley studied, produced malt that gave much improved mash filtration rates in comparison with previous batches of material. These experiments demonstrated that by changing the malting conditions, to give a much shorter steeping cycle (8 h), it is possible to reduce water usage substantially in the malting industry, since only one ‘wet’ cycle was used, and also reduce germination times since optimum alcohol yield was achieved on day 4 germination rather than day 5 for conventional husked barley. This could save costs in terms of water, energy and time for the malting industry. The study also confirmed the potential of hull‐less barley for providing significant benefits for Scotch whisky distillers, both in terms of higher alcohol yields, and increased throughput, by showing that it is possible to overcome some of the filtration issues that have been previously associated with hull‐less barley. This study indicated that the new material was better suited than previous batches to both malt and grain distilling, both in terms of enzyme development and potential distillery performance, and further showed that viscosity problems associated with grain distillery co‐products can be significantly reduced when using hull‐less barley malt in the grain distillery. These would be substantial potential benefits for the Scotch whisky distilling industry.     

Development and Assessment of a Small‐Scale Wort Filtration Test for the Prediction of Beer Filtration Efficiency

A Small‐scale Wort rapid Filtration Test (SWIFT) that predicts beer filtration efficiency has been developed. The test is simple, cost effective and correlates with existing beer filtration tests such as beer V_max membrane (Esser test) and diatomaceous earth (Walton filter) tests. SWIFT has an advantage over existing beer filtration tests as it can be easily incorporated into barley quality laboratories utilising excess wort from extract analyses, thus negating the need for additional sample preparation or to ferment and age beer. Furthermore, the test does not rely on expensive equipment or specially trained laboratory technicians. SWIFT, which may also be used to evaluate degassed beer, is a syringe test that utilises a 13 mm diameter 0.45 μm membrane and is negatively influenced by wort viscosity (P<0.05). It is envisaged that SWIFT may be applied by barley breeding programs for the evaluation of progeny lines to provide a better prediction of beer filtration performance than total wort β‐glucan measurements. In addition, maltsters and brewers could use SWIFT to assess malt samples, and provide early warning of potential beer filtration problems during the brewing process.     

The influence of LOX‐less barley malt on the flavour stability of wort and beer

The aim of this study was to investigate the influence of lipoxygenase‐less (LOX‐less) barley malt on the quality of wort and beer, with the main focus on beer flavour stability. In the current study, pilot‐scale (1000 L) brewing trials were conducted with a control barley malt AC Metcalfe and a LOX‐less barley malt, PolarStar. The results clearly indicated that the LOX‐less barley malt showed less nonenal potential than the control, although LOX activities in both barley malts were relatively low. The beer brewed from the LOX‐less barley malt contained much lower concentrations of trans‐2‐nonenal (T2N) and gamma‐nonalactone, especially after the (forced or natural) aging of the beer, compared with the beer brewed under the same conditions using the control malt. The sensory panel evaluation indicated similar results in the general flavour profile. The freshness scores of beer brewed from the LOX‐less malt were higher than those from the control malt, and this was more pronounced after forced aging. In addition, the beer brewed from LOX‐less malt had a much better foam stability, almost 30 s (NIBEM test). These results confirm that the use of the LOX‐less barley malt was beneficial to beer flavour stability and foam stability. Copyright © 2014 The Institute of Brewing & Distilling     

The structure of barley endosperm – an important determinant of malt modification

Structural differences in barley grains have been classified as either mealy or steely and their relative proportions have been determined using a light transflectance method in three barley samples varying in the degree of steeliness, Target being the most steely and Chariot most mealy with Blenheim being intermediate. These structural differences were found to be associated with differences in the concentration of endosperm components, particularly proteins and β‐glucan. Analysis of nitrogen within the endosperm showed that protein was mainly concentrated in the embryo and distal regions with the inner, mid‐endosperm containing lowest levels. As the total nitrogen (TN) of the grain increased, the mealier samples accumulated nitrogen mainly in the embryo whereas the steely sample had higher levels in the central endosperm. SDS‐PAGE showed no differences in the protein banding pattern at different TN levels. Electron microscopy using immuno‐gold labelling demonstrated that γ‐hordeins were present in sub‐aleurone and outer endosperm whereas the C‐hordeins were found throughout the central endosperm. However, steely areas of central endosperm contained γ‐hordeins. During malting, protein modification in Chariot was more extensive than in Target with 34kD and 97kD hordeins being completely degraded. In Chariot and Blenheim, level of β‐glucan was low and it was evenly distributed throughout the endosperm. In the steelier Target, however, the amount of β‐glucan was higher and was concentrated in the proximal and distal areas of the endosperm. Steely grains (containing high concentrations of protein and β‐glucan) displayed slower water distribution during steeping and later development and distribution of β‐glucanase during germination. As a consequence, the steely sample achieved a lower degree of modification during malting. The structure of the endosperm, therefore, has a prime influence on the evenness of distribution of moisture and enzymes which is crucial for homogeneous modification during malting. © 1999 Society of Chemical Industry     

Effect of cold shock on the enhancement of β‐amylase activity during malting and malt processability for a red sorghum intended for brewing use

The low β‐amylase activity of sorghum malt is a major concern when malts are intended for use in brewing. Several studies have shown that the germination temperature plays an important role in β‐amylase synthesis. In this study, the cold shock treatment was envisioned as a means of improving β‐amylase synthesis during red sorghum malting. The results show that, when a high‐frequency decrease in the germination temperature is used, the obtained malt exhibits a significantly increased β‐amylase activity. This study shows that this increase is not sufficient to consider cold shock as a means of improving β‐amylase activity for red sorghum brewing use, as the processabilty of the malts is unsatisfactory. Copyright © 2015 The Institute of Brewing & Distilling     

Re‐Assessment of the Half‐Grain Modification Method for Assessing Malt Modification

The half‐grain mashing (modification) method proposed by Palmer (J. Inst. Brew., 1975, 81: 408) was reassessed. The intention was to quantify the differences in malt modification in terms of β‐glucan breakdown and clarify the relationship between β‐glucan breakdown and overall modification of the endosperm during malting. This was carried out at 45°C as well as at 65°C, the percentage of weight loss was recorded and the endosperm residue was analysed for β‐glucan content. In general, weight loss was related to modification. Samples, which were modified at higher levels, lost significantly more material during the half‐grain mashing procedure than those which were under‐modified. At a malting process time of 96 h all the varieties had similar weight loss. After mashing the half grains, the β‐glucan contents of the grain residues showed an apparent increase because of loss of non‐β‐glucan materials. However, over the malting period β‐glucan decreased. Chariot malted faster than the other varieties studied. The β‐glucan levels of this variety were reduced by 78% between 48 and 72 h of germination. Significant levels of β‐glucan were degraded and large quantities of starch and protein were released. During the same period of germination, the corresponding samples of Decanter did not show a significant reduction in β‐glucan levels. In contrast, Brazilian variety MN698 lost endosperm material and β‐glucan rapidly by 48 h. These early results suggest that during malting, extract solubilization may or may not accompany β‐glucan breakdown. Therefore, β‐glucan levels in malt cannot be used as an overall index of modification of the endosperm.     

Extraction and Isolation of β‐Glucan from Grain Sources—A Review

A collective report on the extraction and isolation of β‐glucan from grain sources, namely, oat, barley, and wheat is presented. An analysis on the effect of medium, pH, and temperature on the purity and yield of the β‐glucan derived under acidic/alkaline/aqueous/enzymatic conditions is also made. Water extraction and alkali extraction processes are preferred as the yield and recovery of extracted β‐glucan were good. Cost‐effective development of the process for deriving high molecular weight β‐glucan is the current requirement for its wide applications in food and pharmaceutical industries.