Analysis of phenolic compounds in beer: from raw materials to the final product

Two types of lager pale beers were produced at industrial scale according to German Beer Purity Law using the same brewing procedure, but different hop varieties. Beer phenols issued from malt and hop can contribute directly to several characteristics of beer, mainly flavor, astringency, haze, body, and fullness. The aim of this paper was to analyze simple phenolic compounds, total polyphenols and total flavonoids contents, antioxidant activity in raw materials (malt and hops) and in samples taken out from several production stages (after wort production, boiling, fermentation, filtering and pasteurisation). Eighteen different phenolic compounds which belong to the groups of hydroxybenzoic and hydroxycinnamic acid derivates, flavan-3-ols, flavonols and procyanidins dimers were analysed. Among all tested phenolic compounds, 9 compounds were identified in malt, 13 in hops, while 10 in samples taken from the brewing process. Based on the obtained results, it is suggested that the choice of hops is very important for obtaining the desired beer quality and to establish its shelf life.