The influence of time, temperature, pH and calcium carbonate on the activity of the phytase of certain cereals

Abstract

1. Tests have been carried out to investigate the hydrolysis of phytate in wheat, bran, and oats.2. Oats showed practically no phytase activity.3. Wheat phytase had an optimum pH of 5·0–5·1 and functioned at pH values down to 3·0. When hydrolysis had been arrested by acidifying to pH 2·5 for 5 min. or longer, the phytase did not recover when the pH was raised to 5·0 by the addition of sodium bicarbonate.4. There was an almost uniform increase in the rate of hydrolysis between 15 and 50° C.5. The rate of phytate hydrolysis decreased as the reaction proceeded, but the reaction continued until only a very small amount of soluble substrate remained.6. The presence of calcium, under conditions in which it could form insoluble phytate, reduced phytate hydrolysis to a considerable degree.7. These reactions are considered in relation to phytate hydrolysis in the digestive tracts of animals.