Beer Hazes. I. Isolation and Preliminary Analysis of Phenolic and Carbohydrate Components

Abstract

Haze was collected from fresh beer by centrifugation (Haze 1), and the water-soluble portion (over 90% of the total weight) was isolated (Haze 2). Water-soluble portions of hazes from an aged beer (Haze 3) and from a beer forced at 60™ C for 72 hr (Haze 4) were also isolated. Phenolic concentrates of Hazes 1–4 (Preparations 5–8) were prepared by acid-alkali treatment followed by ether extraction. Phenolic compounds were then separated by high performance liquid chromatography on a Microbondapack C18 column. Eleven phenolic acids, two flavonols (quercetin and kaempferol), d-catechin, and l-epicatechin, were identified and quantified in the hazes. Carbohydrates were separated on an Aminex HPX-87 column, and glucose, maltose, fructose, and a dextrin determined after Sep-pack treatment.