CELL WALL DECOMPOSING ENZYMES OF BARLEY AND MALT I.-DETERMINATION AND STABILITY INVESTIGATIONS

Abstract

To determine the cellulase activity of barley or malt, the action on solutions of ethyl-hydroxyethylcellulose brought about by crude extracts of barley or malt is followed by means of viscosity measurements. The observed decrease in viscosity is due to fission of the β-glucosidic linkages of the cellulose ether. Investigations of the heat stability of the cellulase showed that extracts of green malt and cured malt lost about 40% of their activity by heating at 50° C. for 30 min.; the cellulase was almost completely inactivated by treatment at 60° C under the same conditions. Extracts of barley were less heat-sensitive than malt extracts. Kilning of green malt to Pilsner malt (final temperature about 85° C.) caused a loss of only about 50% of the original activity. Both barley and malt cellulase had a pH optimum at approximately pH 5.