Use of phytate determination for estimation of soya proteins in meat products

Phytates present in vegetable protein preparations were used to measure the degree of substitution of meat proteins by vegetable proteins. In two series of beef blends with soybean protein preparations 6–30% of meat proteins was substituted by soybean proteins. To some blends pickling solutions containing i.a. Na₄P₂O₇ were added. Phytic phosphorus was determined colorimetrically, after extraction with HCl, in raw, pasteurized, and sterilized blends both with and without addition of inorganic phosphate. In blends with no pickling solution the contents of phytic P increased linearly with increasing contents of soybean proteins and the linearity was not influenced by the heat treatment. In blends containing the pickling solution the amount of phytic P increased with increasing heat treatment conditions and with increasing amount of inorganic phosphate added. These relationships reduce the applicability of the method for practical estimation of substitution degree of meat by vegetable proteins.