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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. [ABSTRACT FROM AUTHOR]

Arabinoxylan is a major polysaccharide found in barley and wheat. As this polysaccharide has been reported to be involved in wort viscosity and filterability, as well as β-glucan, it has become increasingly important in beer brewing in recent years, despite the limited availability of a measurement methodology for arabinoxylan. In this study, we developed a simple method for determining arabinoxylan content in wort and beer products using a commercially available xylose determination kit. The results show a relationship between arabinoxylan and the viscosity of wort and beer products. These results were consistent with previous reports, suggesting that this simple method can be used to observe the behavior of arabinoxylan during malting and brewing. [ABSTRACT FROM AUTHOR]

In general, barley with smoother degradation of seed storage material (modification) is known to have lower seed dormancy and a higher risk of pre-harvest sprouting (PHS). The Qsd1 and Qsd2 genes affecting seed dormancy have also been reported to affect malting characteristics. To overcome this situation, barley with an excellent balance of modification and seed dormancy was screened among the mutant population derived from 'Nittakei 68 (N68)'. In the mutant lines screened, 'N68-411' exhibited a moderate seed dormancy similar to that of 'N68', but with higher modification. It was considered that 'N68-411' was mutated in a different gene from Qsd1 and Qsd2 , resulting in no significant change in seed dormancy, only in modification. 'N68-411' also showed rapid modification during germination, suggesting a possibility of shorter germination time in malting process. Analysis of progenies from 12WY375/N68-411 and Xena/N68-411 indicated that the 'N68-411' trait was inherited and associated with a small number of genes. [Display omitted] • Sustainability of barley and malt production. • Discovery of the barley mutant line with novel traits. • Better balance between malt modification and seed dormancy. • Possibility of a shorter germination time in the malting process. [ABSTRACT FROM AUTHOR]

Abstract The lipoxygenase-1-null (LOX-less) trait has positive effects on beer quality, and in particular, improvement of flavor stability by reduction of beer deteriorating substances such as trans -2-nonenal (T2N). 'SouthernStar' was successfully developed as the first LOX-less malting barley variety in Australia by introducing LOX-less trait into 'Flagship' by successive backcross and molecular marker assisted selection (MMAS). 'Flagship' is a two-rowed malting barley variety in Australia and it was used as the recurrent parent for the successive backcrossing. The yield potential, agronomic performance, disease resistance and the general malting quality were almost identical between 'SouthernStar' and 'Flagship'. To evaluate effects of LOX-less trait on beer quality, the brewing trials were conducted using a pilot-scale brewing apparatus. The wort and beer quality were similar between 'SouthernStar' and 'Flagship'. The effect of the LOX-less trait on the reduction of beer deteriorating substances such as T2N and trihydroxyoctadecenoic acid (THOD) contents was clearly verified in this study. The scores for total staleness of the test beers were significantly lower than those of the control beers under several storage conditions in one trial. Highlights • A new lipoxygenase-1-less (LOX-less) malting barley variety 'SouthernStar' developed by backcrossing. • Similar agricultural characteristics and malting quality as a recurrent parent 'Flagship'. • Reduction of trihydroxyoctadecenoic acid (THOD) and trans -2-nonenal (T2N) contents in beer by LOX-less trait introduced. • Improvement of flavor stability evaluated by sensory analysis for stale beer. [ABSTRACT FROM AUTHOR]