Dephytinising efficacy of wheat phytase in enhancing the bioaccessibility of minerals in high phytate foods

Abstract

Iron deficiency anemia and zinc deficiency are major public health problems in developing world which are attributable to the poor bioavailability due to the presence of phytic acid in plant foods. Dephytinisation by enzymatic application is identified to be ideal approach, however the commercial availability of phytases from food sources is scarce. This prompted us to undertake the investigation on the dephytinisation of the high phytate food matrices by utilising the indigenous phytase of wheat. Attempts were made to enhance the phytase activity by various approaches. Phytase activity of wheat was increased by fivefold on sprouting (96 h). The native phytase of wheat activated by incubation at optimum conditions of pH and temperature has shown an increase in the activity as a function of time. Isolation and partial purification of phytase from sprouted wheat further increased the activity by 1.5 fold. Thermostability of phytase was enhanced by additives such as sodium citrate, calcium chloride and magnesium sulphate. Addition of phytase activated wheat flour to soya flour enhanced the bioaccessible iron by 1.7 fold. Partially purified phytase enhanced the bioaccessible iron by 1.9 fold and zinc by 2.4 fold in defatted soya flour reflecting dephytinisation. Investigation on complete purification of phytase are warranted.