EUROPEAN BREWERY CONVENTION-HAZE AND FOAM GROUP ORIGIN OF CARBOHYDRATE IN BEER SEDIMENTS

Abstract

Carbohydrate-containing sediments can be divided into two types: in the commoner type the polysaccharide is associated with protein and polyphenol, and the sediment is chemically related to haze; the second type of sediment is almost entirely carbohydrate and may give rise to a gel. An enzymic procedure has been developed which allows one to determine whether the carbohydrates are derived from an α-glucan (dextrin) or a β-glucan. Addition of ethanol (20%, v/v) to the beer precipitates a mixture of substances including high molecular weight α- and β-glucans. However, the polysaccharide which becomes associated with protein and polyphenol appears to be exclusively α-glucan. α-Glucans readily give cyclodextrins which are well known to form inclusion complexes with a wide variety of molecular types. It is suggested that inclusion complexes of this type are involved in protein-polyphenol-polysaccharide sediments and may modify the rate of polymerization reactions.