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.

Quantitation Method for Polyfunctional Thiols in Hops (Humulus lupulus L.) and Beer Using Specific Extraction of Thiols and Gas Chromatography-Tandem Mass Spectrometry.

A method for the quantitation of six polyfunctional thiols, 4-methyl-4-sulfanylpentan-2-one (4MSP), 3-sulfanyl-4-methylpentan-1-ol (3S4MP), 3-sulfanyl-4-methylpentyl acetate (3S4MPA), 3-sulfanyl-3-methylbutan-1-ol (3S3MB), 3-sulfanylhexan-1-ol (3SH), and 3-sulfanylhexyl acetate (3SHA), in hops and beer without organic mercury compounds was developed. The method employed specific extraction of thiols using a silver ion solid phase extraction (SPE) cartridge and gas chromatography-tandem mass spectrometry (GC-MS/MS). For all thiols analyzed, good linearity was achieved by adding thioglycerol as an analyte protectant. Recoveries for both hops (74-100%) and beer (79-113%) were acceptable, and the repeatability for both was also good (relative standard deviations of 2.8-8.4%). The limits of detection for the six polyfunctional thiols were below their odor thresholds in beer. The method was applied to quantitation of hops and beer flavored with thiol-containing hop varieties. Due to their detected levels and level variations in different beers, 4MSP and 3S4MP are thought to be important polyfunctional thiols for the characteristic flavor of hop varieties.

Xanthohumol, a prenylated chalcone from Humulus lupulus L., inhibits cholesteryl ester transfer protein.

High density lipoprotein (HDL)-cholesterol levels are correlated with a low risk of atherosclerosis. The inhibition of cholesteryl ester transfer protein (CETP), which catalyses cholesterol transfer between lipoproteins, leads to an increase in HDL-cholesterol and is expected to be the next anti-atherogenic target. This study revealed that xanthohumol, a prenylated chalcone, showed the highest inhibition against CETP from screening of natural products in various plants. We investigated the inhibitory activity of some chalcones and flavanones. Naringenin chalcone showed weak CETP inhibition compared with xanthohumol. In addition, isoxanthohumol and naringenin drastically decreased the inhibitory activity. These results suggest that the prenyl group and chalcone structure of xanthohumol were responsible for the CETP inhibitory activity.