Phytic Acid Contents of Wheat Flours from Different Mill Streams

The phytic acid contents of eight fractions of wheat flours from different mill streams and those in wheat brans,which were separated by different sieves into various sizes,were determined and analyzed.A rapid method for phytic acid assay by adding thioglycolic acid(mercapto acetic acid)with 2,2-bipyridine was used,with an acidic iron-Ⅲ-solution of known iron content.The amount of phytate was indicated by the decrease in iron in the supernatant.Significant differences were observed in phytic acid content among different milling streams and different cultivars(P<0.05).On an average,coarse bran had the highest phytic acid content(53.85 mg g-1),and the shorts had 28.48 mg g-1.The B5 break flour had a higher phytic acid content(4.8 mg g-1)than the B7(2.75 mg g-1)and B8(2.03 mg g-1)reduction flours.Lower values were found in the B3,B6 and B7 flours(1.07,0.79,and 0.76 mg g-1,respectively).The phytic acid contents of bran decreased with smaller bran sizes,ranging from 54 to 5.09 mg g-1.