title: Determination of phytase activity in cereal grains by direct incubation.
abstract: In contrast to supplemented microbial phytases, considerably lower cereal phytase activities were found after application of an enzyme solution extracted in citrate/NaOH buffer (pH 5.5) for 1 h as compared with the direct incubation of the plant material. Differences between both methods obtained were 70% for wheat and spelt and 50% for barley and rye. The determination of phytase activity of a wheat sample by direct incubation was affected by the sample size and amount of substrate (Na-phytate) added. Optimal conditions are a maximal level of phytase activity of < or = 0.05 U incubated for 60 min in a buffered solution (citrate/NaOH, pH 5.5) with 10 ml of 32.6 mmol/l Na-phytate at 37 composite function C. Possible reasons for the differences between both methods and for the factors affecting phytase activity by direct incubation are discussed.
authors.affiliation: Institute of Animal Nutrition, Hohenheim University, Stuttgart, Germany. bf.zimmermann@t-online.de
authors.forename: B
authors.initials: B
authors.lastname: Zimmermann
authors.forename: H-J
authors.initials: HJ
authors.lastname: Lantzsch
authors.forename: U
authors.initials: U
authors.lastname: Langbein
authors.forename: W
authors.initials: W
authors.lastname: Drochner
mesh_terms: D010832:6-Phytase / Q000378:metabolism*; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002523:Edible Grain / Q000201:enzymology*; D001467:Hordeum / Q000201:enzymology; D010316:Particle Size; D012434:Secale / Q000201:enzymology; D013379:Substrate Specificity; D014908:Triticum / Q000201:enzymology
chemical_list: D010832:6-Phytase