Phytase activity in extracts of flour and bran from wheat cultivars:: enhanced extractability with β-glucanase and endo-xylanase

Phytase (EC 3.1.3.8) hydrolyzes phytic acid to myo-inositol and inorganic phosphate through intermediate myo-inositol phosphates. Microbial phytase has been employed to minimize the negative effects of phytic acid in cereal-based feeds, however, other sources such as wheat, would be natural alternatives. Investigations were therefore carried out to determine the levels of phytase activity in various cultivars and how the extraction of the enzyme may be enhanced using buffers fortified with glycanases. We screened 23 cultivars and the results showed that bran from hard white wheat cultivars had relatively lower levels of activity, ranging from about 1.5 to about 2.5 FTU/g bran, whereas hard red wheat cultivars had much higher levels, ranging from approximately 2 to 5.5 FTU/g bran. These levels were greatly enhanced, up to 5-fold, when extraction buffer contained a commercial preparation consisting of beta-glucanase (EC 3.2.1.6) and endo-xylanase (EC 3.2.1.8) (Natugrain) (opt 1%) from BASF. The effect of glycanases was concentration and cultivar dependent, but not significantly influenced by temperature exposure of mixtures of samples with extraction buffers prior to extraction. Relative increases were more substantial in hard white than in hard red wheat cultivars. The additional value of supplementing grain-based diets with glycanases for monogastric animals is discussed. (C) 2003 Elsevier Ltd. All rights reserved.