Development of a flavor hop (Humulus lupulus L.) cultivar, 'Furano Magical', with cones rich in 4-methyl-4-sulfunylpentan-2-one.

BACKGROUND: Flavor hops (Humulus lupulus L.) are recognized as key raw materials that impart unique flavors to beer, especially in the emerging craft-beer industry. In this study the sensory evaluation of hop cone aromas using hop water extract by boiling (HWEB) was applied to develop new flavor hop cultivars in a screening from tens of varieties and breeding lines. RESULTS: The sensory scores of HWEB showed a significant correlation with polyfunctional thiol content in hop cones, including substances such as 4-methyl-4-sulfunylpentan-2-one (4MSP) and 3-sulfunyl-4-methylpentan-1-ol (3S4MP), which are known to be difficult to analyze mechanically. As a result of the sensory evaluation of HWEB, a breeding line, 'K906901060' was found to have a strong fruity note. Subsequent chemical analyses revealed that this cultivar had 80-136 µg kg-1 of 4MSP in its cones, which is similar to the concentration present in current leading flavor hop cultivars, such as Citra (37-114 µg kg-1 ) and Simcoe (2-112 µg kg-1 ). Beer late-hopped with K906901060 provoked a greater tropical flavor impression than beer hopped using Nelson Sauvin hops. CONCLUSION: The sensory evaluation of HWEB was indicated to be useful to search for hops containing polyfunctional thiols. The plant was registered, as 'Furano K906901060 Go' in Japan, in the EU, and in the USA, and the cultivar was given the commercial name 'Furano Magical'. This cultivar was derived from a cross performed in 1989 and had been kept as a mid-mother plant from 1997, until being selected in 2014, as described here. © 2022 Society of Chemical Industry.

Effect of "Late Harvest" of Hops (Humulus lupulus L.) on the Contents of Volatile Thiols in Furano Beauty, Furano Magical, and Cascade Varieties.

In recent years, many hop varieties with unique aromas, so-called "flavor hops", have been bred and grown. Here, we investigated the effect of late-harvested hops using three flavor hop varieties; Furano Beauty, Furano Magical, and Cascade. The sample hops were harvested at different days after flowering (DAF): DAF 45 (normal harvest), DAF 65, DAF 75, and DAF 85. We measured the volatile thiols in sample cones. The results indicated that 4-methyl-4-sulfanylpentane-2-one contents showed almost no change or a slightly decrease with a delay in harvest, whereas 3-sulfanyl-4-methylpentan-1-ol (3S4MP) content in late-harvested samples increased several fold in comparison with normal-harvested samples. Additionally, 3S4MP contents in the beers brewed with DAF 65 samples were several times higher than those using DAF 45 ones. From these results, we propose a new method to control 3S4MP content in hop cones by changing its harvest date.

Breeding and brewing quality of the Canadian malting barley variety 'CDC Goldstar' lacking lipoxygenase-1.

Various types of malt quality profiles have been investigated to benefit the North American brewing industry. Herein, we report the development and brewing quality of the hulled, two-row malting barley (Hordeum vulgare L.) variety 'CDC Goldstar' lacking lipoxygenase-1 (LOX-1-less). This new variety offers a novel malt type for the improvement of beer flavor stability. The agronomic performance of 'CDC Goldstar' was tested in the Western Cooperative Two Row Barley Registration Trials during 2013-2014. In addition to high lodging tolerance, the new variety showed 6% higher yield than the current leading variety 'CDC Copeland'. The malt quality of 'CDC Goldstar' showed higher diastatic power and lower wort ß-glucan content than 'CDC Copeland' and controllable proteolytic modification (soluble nitrogen and Kolbach Index). Pilot- (100 L) and commercial-scale (5,000 L) brewing trials were conducted using 'CDC PlatinumStar', another LOX-1-less variety with a low enzymatic profile, as the control variety. Absence of the LOX-1 trait from 'CDC Goldstar' maintained trans-2-nonenal levels in aged beers as low as those in other LOX-1-less varieties without affecting major beer parameters, such as ester and aldehyde content or foam stability. The newly developed 'CDC Goldstar' malting barley provides added value for the beer industry and consumers.

Construction of gene expression system in hop (Humulus lupulus) lupulin gland using valerophenone synthase promoter.

The promoter region of the valerophenone synthase (VPS) gene was isolated from hop (Humulus lupulus). VPS, a member of the chalcone synthase (CHS) super-family, catalyzes the biosynthesis reaction of the hop resin that significantly accumulates in the cone's secretory gland called the "lupulin gland". The typical H-box and G-box sequences, which exist in many plants' CHS promoters and act as cis-elements for tissue specificity, UV-light induction, etc., were not found in the isolated VPS promoter, although the H-box-like sequence (CCTTACC, CCTAACC) and the core sequence (ACGT) of the G-box were observed. The transformation experiment using the VPS promoter-UIDA gene fusion revealed that the promoter acts not only in the lupulin gland but also in the glands of leaf and stem. On the other hand, the VPS promoter activity was not induced by UV-irradiation.