BEER QUALITY ASSURANCE BY CONTROLLING WORT POLYPHENOLIC CONTENT WITH ADSORPTION METHOD

This research explores feasibility of adsorption method used for regulating polypenols content in wort with a view of improving beer quality. It examines adsorption of polyphenols (quercetin, gallic acid, rutin) from pure substance solutions, their mixtures and beer wort treated by sorbents that differ by origin, making, structure and surface chemical composition. The work determines patterns and specific features of polyphenols adsorption with activated carbons. To describe adsorption mechanism more precisely, we specified structure, surface chemical condition, and calculated adsorption parameters using equations of Langmuir, Freundlich and Dubinin-Radushkevich, and the multilayer adsorption theory (BET model). It is demonstrated that polyphenols adsorption mechanism depends on carbon characteristics and is of physical nature that reveals itself in dispersion interaction in micropores and in specific one with oxygen-containing functional group (OFG) on carbon surface. Polyphenol competitive adsorption in mixture and wort recognized. At polyphenols adsorption from model solutions and wort, carbon sorbents are identified to share sufficiently close sorption characteristics. We performed comparative evaluation of quality characteristics of beer produced from activated carbons treated and untreated worts. It is shown that beer samples produced from unhopped wort filtered through semi-coke adsorption, meet regulatory standards requirements of safety by organoleptic, physical and chemical indicators. Moreover, beer obtained from semi-coke treated wort exceeds control sample in terms of organoleptic and stability ensuring indicators.