AbstractThe quantitative changes of phytates taking place during preparation of some sorts of Polish bread were investigated. Sorts of bread chosen for investigation were produced from raw materials with a high phytate content: flour of high extraction, soy bean flour, bran and wheat germ. The content of phytic phosphorus was determined in all components (raw materials), intermediate products and bread. The degree of phytate hydrolysis during preparation of different sorts of bread varied and depended both on the initial amount of these compounds in raw materials used and on the technological process adopted. The most intensive hydrolysis of phytate took place during preparation of rye breads: about 80% of the initial value were hydrolyzed. Almost in all sorts of wheat bread the degree of hydrolysis of phytate was much less: only about 25–60% of these compounds were decomposed. In case of “mixed” bread (wheat and rye one) undecomposed phytate varied from 6% to 49% of the initial