Further Studies on the Foam-Stabilizing Substances in Beer

Abstract

A material containing both carbohydrate and protein together with some ferulic acid, and which has pronounced foam-stabilizing activity, has been isolated from beer. A fraction similar in constitution and activity to the beer constituent has been recovered from an aqueous extract of barley flour. These materials are comparable with a glycoprotein present in wheat flour; the latter has been shown to be effective in the stabilization of beer foam. There was little difference in the amount and activity of extracts prepared from different varieties of barley.

Wheat Variety and Barley Malt Properties: Influence on Haze Intensity and Foam Stability of Wheat Beer

“…Using Tinos wheat for brewing increased the head retention of the beer by 20%. Remarkably, in the wheat beers, the nitrogen HRV were related to the NIBEM (R 2 = 0.65; P < 0.01) and CO 2 Rudin (R 2 = 0.45; P = 0.06) values obtained.…”

“…Although wheat does not necessarily have a higher overall protein content than barley, wheat contributes more high molecular weight proteins to the wort 27,34 . These wheat proteins 4,27,35 , more specifically wheat glycoproteins 2 , have been suggested to be related to the superior foam characteristics of wheat beers. Wilde et al 38 and Clark et al 10 isolated lipid binding proteins from wheat (puroindolines) which can bind to free lipids in beer, reducing lipid induced destabilisation of beer foam.…”

Wheat and other Triticum grains

“…In particular, wheat beers are often distinguished by spicy, fruity and biscuit notes and a creamy and stable head foam (Brijs et al, 2002). It has been suggested that the typical foam characteristics are related to the presence of high molecular weight wheat proteinaceous material (Leach, 1968), more specifi cally glycoproteins (Anderson, 1966), higher beer viscosity and/or a fi ner foam bubble size distribution (Depraetere et al, 2004). Wheat arabinoxylans and β-glucans have been claimed to increase beer viscosity reducing the drainage of liquid from foam, thereby increasing foam stability (Kolbach and Kremkov, 1968).…”

Solubilisation and Degradation of Wheat Gluten Proteins by Barley Malt Proteolytic Enzymes

“…Besides economical profits, creamy foam and a superior head retention of the resulting products are the major reported advantages. It has been suggested that the typical foam characteristics are related to the presence of high molecular weight wheat proteinaceous material 4,14,19 , more specifically glycoproteins 3 . In line with the above, avoiding excessive wheat proteolysis during mashing leads to beneficial foam properties 4 .…”

“…It is therefore tempting to speculate that precipitates rather than hazes are formed when the MW of the proteins is too high. High and intermediate MW proteins have also been claimed to enhance foam stability 3,4,14,19 and fullness of beer 16 . At the pH of brewing, wheat gluten proteins hardly contribute to the amino acid level of the wort, which are important for yeast growth and buffering.…”