A Discussion of Polyphenols in Beer Physical and Flavour Stability

Abstract

Generally referred to as polyphenols (PPs), beer flavonoids such as the flavan-3-ols and their condensed products, the proanthocyanidins, represent a class of readily oxidizable compounds capable of hindering or preventing the oxidation of other molecules present in beer. Flavan-3-ol and proanthocyanidin capacity to improve oxidative stability has been well established in other food systems, and thus these antioxidants have recently gained significant consideration as potential beer flavour modifiers and/or stabilizers. The duality of their presence in beer is that PPs complex with proteins in the beer matrix to form temporary and permanent hazes. Undesirable physical instability caused by PP-protein interactions can be resolved via use of adsorptive resins such as polyvinylpyrrolidine. While there is no doubt that polyphenol removal increases beer shelf stability in terms of haze formation, the impact of polyphenol removal on beer flavour remains unresolved. This review discusses the sources, content and impact of polyphenol presence and removal on beer physical and flavour stability.

Antiradical and reducing potential of commercial beers

“…Flavour deterioration is connected with oxidative degradation of beer constituents by reactive oxygen species such as oxygen or nitrogen radicals as well as by non-radicals with the ability to oxidise or convert molecules into oxidising radicals. However, beer is rich in substances that can help protect against oxidation, the most important of which are sulphurcontaining compounds, bitter hop resins, vitamins, and Maillard reaction products (Aron & Shellhammer 2010). Moreover, beer contains various phenolic compounds from malt or hops, which also exhibit antioxidant properties (Leitao et al 2011(Leitao et al , 2012.…”

Beneficios de los polifenoles contenidos en la cerveza sobre la microbiota intestinal

“…Sin embargo, la elección de las materias primas de partida y el proceso de fabricación de los distintos tipos de cerveza van a provocar que los tipos y contenidos en polifenoles varíen y que, por lo tanto, se puedan encontrar diferentes relaciones con la microbiota intestinal, con unos resultados para el hospedador diferentes (11).…”

Monitoring of Beer Filtration Using Photon Correlation Spectroscopy (PCS)

“…It was interesting to consider the fouling of pores to a reduced diameter through application of Equation 1. By entering the values of initial flux and flux at six min (at end of intermediate pore blockage) and the stated initial membrane pore diameter of 0.45 µm, the pore diameter at 6 min was calculated as 0.22 µm.…”

“…Particle size influences both beer filterability and its shelf life. Particles that remain in the permeate are mainly formed by proteins, carbohydrate and polyphenols, and often induce later haze formation, reducing the quality of the product 1,4,14 .…”