DisplayTitle

Barley Contains Two Cationic Acetylxylan Esterases and One Anionic Feruloyl Esterase

¹Department of Food Science and Technology, University of California, Davis, CA 95616-8598. ²Food Materials Science Division, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK. ³Corresponding author. Phone: 530/752-1467. Fax: 530/752-4759. E-mail: cwbamforth@ucdavis.edu

Various carbohydrate-active esterases are detected in extracts of malted barley when analyzed by polyacrylamide gel electophoresis. The slowest migrating and most heat-resistant of these are relatively cationic acetylxylan esterases. Two such activities, one with a high affinity for esterase substrates including acetylated xylan, and one with a low affinity, are indicated. These enzymes did not hydrolyze methyl ferulate. A relatively heat-labile anionic feruloyl esterase has also been purified. It has some, albeit low, ability to act on acetylated xylan. The feruloyl esterase effects extensive release of ferulate from endosperm cell walls isolated from barley, whereas the acetylxylan esterases are only capable of very limited release of acetate.