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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.

One of the ways to improve colloidal stability and organoleptic properties of beer is to control polyphenol constituents in unhopped beer applying adsorption method with carbon sorbents, sorption progressing dynamically. The adsorption of polyphenol constituents from unhopped wort under dynamic conditions using carbonic sorbents has been studied in order to prove the possibility of using cheap carbon ABG and «Purolat Standard». According to the obtained data, carbon sorbent «Purolat Standard» can be recommended for practical realization and designing the process of adsorption under dynamic conditions. The possibility of designing the process of content control of unhopped wort using carbon sorbent «Purolat Standard» has been proved experimentally. The calculation method for filter parameters and the modes of adsorption of polyphenol constituents from unhopped wort has been suggested. The method is based on the outward diffusion equation of adsorption dynamics for isothermal line using the Dubinin-Radushkevich adsorption constants and the kinetic analysis data. The efficient filter parameters and the modes of adsorption of polyphenol constituents from unhopped wort, which lead to the improvement of colloidal stability and organoleptic properties of beer, have been calculated. The method of waste sorbent «Purolat Standard» recovery after adsorption of polyphenol constituents from unhopped wort has been suggested. The dependence of filtration rate on initial content of polyphenol compounds in wort has been found out. The required equipment and the operational modes of the apparatus providing the improvement in beer quality by the control of polyphenol constituents in wort have been recommended.

The adsorption of gallic acid on active carbons of different ranks with different pore structure and chemical state of the surface is investigated. The regularities and features of the adsorption process are established. It is revealed that the adsorption isotherm of gallic acid from the aqueous solution with activated carbon of AG-OB-1 rank refers to the L-type isotherms by Giles's classification, and AC adsorption isotherm of ABG and Purolat-Standard ranks - to the S-type isotherms. L-type isotherm gives evidence concerning the flow of physical adsorption. With S-type isotherm is the adsorption described, at which the strength of the interaction between the solute and the adsorbent is less than the force of interaction between the adsorbed molecules, which can be explained by the formation of hydrogen bonds. It was found that the maximum adsorption of gallic acid with carbon sorbents changes in the following sequence - "Purolat-standard" > ABG > AG-OV-1. The mechanism of adsorption of gallic acid on active carbons is offered. Proceeding from the structure, the chemical state and the main adsorption parameters of active carbon, we can assume that the adsorption of gallic acid has physical nature. It can take place in pores, both due to dispersion interaction (of van der Waals forces) and due to the interaction between the active carbon surface functional groups, containing oxygen with carboxyl and hydroxyl groups of gallic acid. The values of adsorptive capacity testify to the dependence of the adsorption efficiency on the structure and physical-chemical properties of the sorbent. It has been determined that by the absorption of gallic acid specific interaction makes greater contribution. It is shown that the results obtained can be applied to create adsorption technologies on removing gallic acid from the sewage containing individual components and from the mixture with other polyphenols, including beer wort.