Interactions Between Dissolved beta-Glucans and Medium-Chain Fatty Acid Ethyl Esters in Model Beer Solution and Their Impact on Filterability

As shown in previous studies, not only the concentration of the dissolved beer ingredients but also their molecular size could influence their filterability. Therefore, polysaccharides of malt, especially P-glucan, are reported to have the greatest impact on filtration behavior. In the present study, the effects of barley (1,3; 1,4)- and yeast (1,3; 1,6)-beta-glucan combined with aroma-relevant substances of beer were studied in Kieselguhr and membrane filtration (polyethersulfone, 0.45 mu m) using ethanolic (4% w/w) model solutions. An increasing P-glucan concentration was found to have a negative impact on both applied filter types. The concentration increase of barley beta-glucan to 300 mg/L decreased the filtrate flux more than 40% during membrane filtration. In contrast, pure medium-chain fatty acid (MCFA) ethyl esters had no effect on filterability. Mixed with (1,3; 1,4)-beta-glucan, the filtrate flux decreased from 400 kg/(h x m(2)) to less than 250 kg/(h x m2). A decrease of MCFA ethyl ester up to 90% was measured in the filtrate. Compared with barley beta-glucan, an equivalent concentration of yeast beta-glucan caused a flux decrease of more than 95% during membrane filtration. In summary, synergistic effects on filterability with polysaccharides and fermentation byproducts could be shown.     «

As shown in previous studies, not only the concentration of the dissolved beer ingredients but also their molecular size could influence their filterability. Therefore, polysaccharides of malt, especially P-glucan, are reported to have the greatest impact on filtration behavior. In the present study, the effects of barley (1,3; 1,4)- and yeast (1,3; 1,6)-beta-glucan combined with aroma-relevant substances of beer were studied in Kieselguhr and membrane filtration (polyethersulfone, 0.45 mu m) us...     »