Xanthohumol
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Xanthohumol (XN) is a phenolic compound extracted from hops during the brewing process. More specifically, it is a prenylated chalcone. Special attention has been given to XN due to its significant health benefits and anticarcinogenic properties.[1][2] Beer is an exclusive source of XN in human diet but its content is usually low (less than 0.2 mg/L in macro beers) since it undergoes extensive thermal isomerization into the prenylated flavonoid isoxanthohumol (IXN) during the brewing process.[1][2][3][4][5] For this reason, brewers have been particularly interested in the production of beer with higher XN concentration considering its potential health benefits for the consumers.
In spite of its relatively low levels in commercial beers ( Table 12.8 ), the prenylated chalcone xanthohumol ( 53 ) has gained considerable interest because of its potential cancer chemopreventive properties ( Gerhauser et al. , 2002a; reviewed in Gerhauser, 2005 ). Levels up to 1.2 mg/l have been reported in stout and porter-style beers ( Walker et al. , 2004 ). Recently, attempts have been made to increase the amount of xanthohumol in beer by modifi cations in the brewing process. Generally, xanthohumol is isomerized to the fl avanone isoxanthohumol ( 55 , see section “ Flavanones ” ) during wort boiling. Wunderlich et al. (2005) used xanthohumol-enriched hops products combined with a late hops dosage during wort boiling to effectively increase the xanthohumol content in beer. Interestingly, xanthohumol was found to form stable complexes with several high molecular weight substances in a size range of 300–600 kDa. In an experimental setup, dark beers with more than 10 mg/l xanthohumol were achieved by usage of roasted malt or special xanthohumol-enriched roasted malt extracts ( Wunderlich et al. , 2005 ). [6]
Strategies for enriching XN content in beer[edit]
These methods, described by Wunderlich and Back and patented in 2004, allow the production of unfiltered lager beers with 3 mg/L of XN and filtered dark beers with more than 10 mg/L.[1][5] More heavily-hopped craft beers will likely contain even higher levels.
- Late addition of hops during boiling or whirlpool, combined with rapid chilling.[1][2][3][4]
- Reduced boiling time.[1]
- Lower temperature during wort boiling.[1]
- The use of high hydrostatic pressure.[1]
- High gravity brewing.[1]
- Decoction mashing.[1] (Melanoidins appear to have a protective effect from XN isomerization and adsorption onto PVPP.[1][2][3])
- The use of different raw materials such as roasted malts and XN-enriched hop products (obtained by ethanol-CO2 extraction).[1][2][4][5] Hops with higher α-acid levels have more XN.[4][5]
- Pitching lower amounts of yeast and/or recycling yeast.[1] (XN adsorbs onto yeast cells.[1][2][3])
- The use of dry-hopping.[1]
- Limited filtration and/or limited usage of PVPP.[1]
- The use of hydrodynamic cavitation.[7]
- Drink fresh beer, because XN concentration decreases during storage.[2][3][4]
See also[edit]
- De Keukeleire J, Ooms G, Heyerick A, Roldan-Ruiz I, Van Bockstaele E, De Keukeleire D (2003) Formation and accumulation of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol during flowering of hops (Humulus lupulus L.). J. Agric. Food Chem 51:4436–4441
References[edit]
- ↑ a b c d e f g h i j k l m n o Carvalho DO, Guido LF. A review on the fate of phenolic compounds during malting and brewing: technological strategies and beer styles. Food Chem. 2022;372:131093.
- ↑ a b c d e f g Wannenmacher J, Gastl M, Becker T. Phenolic substances in beer: Structural diversity, reactive potential and relevance for brewing process and beer quality. Compr Rev Food Sci Food Saf. 2018;17(4):953–988.
- ↑ a b c d e Habschied K, Košir IJ, Krstanović V, Kumrić G, Mastanjević K. Beer polyphenols—bitterness, astringency, and off-flavors. Beverages. 2021;7(2):38.
- ↑ a b c d e Callemien D, Collin S. Structure, organoleptic properties, quantification methods, and stability of phenolic compounds in beer—a review. Food Rev Int. 2009;26(1):1–84.
- ↑ a b c d Collin S, Jerković V, Bröhan M, Callemien D. Polyphenols and beer quality. In: Ramawat KG, Mérillon J-M, eds. Natural Products. 1st ed. Springer; 2013:2334–2353.
- ↑ Gerhäuser C, Becker H. Chapter 12: Phenolic compounds in beer. In: Preedy VR, ed. Beer in Health and Disease Prevention. Academic Press; 2009:124–144.
- ↑ Martinez-Gomez A, Caballero I, Blanco CA. Phenols and melanoidins as natural antioxidants in beer. Structure, reactivity and antioxidant activity. Biomolecules. 2020;10(3):400.