A review on the fate of phenolic compounds during malting and brewing: Technological strategies and beer styles

This review provides an overview on the influence of malting and brewing on the overall phenolic content of barley malt and beer. Beer phenolics are mainly originated from barley malt and can be found in free and bound forms, in concentrations up to 50% lower comparing to sweet wort. The use of roasted malts, in combination with proper milling and high mashing temperatures at low pH can lead to a release of bound phenolic forms and increased extraction. New technological strategies such as special yeasts, manipulation of enzymatic activity and dry-hopping may be relevant to improve the phenolic profile of beer and attain phenolic levels with benefits both for beer stability and consumer's health. As the content of free ferulic acid in beer only accounts up to approximately 15% of total content, further studies should put emphasis on its bound forms in different beer styles and non-alcoholic beers.

The Influence of Hop Phenolic Compounds on Dry Hopping Beer Quality

Background: The article considers the phenolic hop compounds’ effect on the quality indicators of finished beer. The topic under consideration is relevant since it touches on the beer matrix colloidal stability when compounds with potential destabilizing activity are introduced into it from the outside. Methods: The industrial beer samples’ quality was assessed by industry-accepted methods and using instrumental analysis methods (high-performance liquid chromatography methods—HPLC). The obtained statistical data were processed by the Statistics program (Microsoft Corporation, Redmond, WA, USA, 2006). Results: The study made it possible to make assumptions about the functional dependence of the iso-α-bitter resins and isoxanthohumol content in beer samples. Mathematical analysis indicate interactions between protein molecules and different malted grain and hop compounds are involved in beer structure, in contrast to dry hopped beer, where iso-a-bitter resins, protein, and coloring compounds were significant, with a lower coefficient of determination. The main role of rutin in the descriptor hop bitterness has been established in kettle beer hopping technology, and catechin in dry beer hopping technology, respectively. The important role of soluble nitrogen and β-glucan dextrins in the perception of sensory descriptors of various technologies’ beers, as well as phenolic compounds in relation to the formation of bitterness and astringency of beer of classical technology and cold hopping, has been shown. Conclusions: The obtained mathematical relationships allow predicting the resulting beer quality and also make it possible to create the desired flavor profiles.