The molecular weight distribution of β-glucan in wort from malts of different barley varieties at different stages of malting

Abstract

The molecular weight distributions of β-glucans from congress worts of the barley genotypes Minerva (feed barley) and Triumph (malting barley) at 0–9 days of malting were studied by gel permeation chromatography. The amount of β-glucan was estimated using a glucose determination method and a specific fluorometric method based on an increase in the fluorescence intensity of Calcofluor when binding to high molecular weight (>10,000) β-glucan. The amount of extracted β-glucan was slightly higher for Minerva than for Triumph barley at all stages of germination. The elution patterns of β-glucan in congress worts made from the two barley genotypes were similar, although the high molecular weight β-glucan analysed in worts from Triumph was decomposed during malting at a fasterrate than in those from Minerva. The extracted high molecular weight β-glucans were found to have molecular weights in the range of 104–106. The differences in the contents of high molecular weight β-glucans cannot explain all the variation in viscosities of the worts.