evaluation of the effect of fermentation, hydrothermal treatment, soda, and table salt on phytase activity and phytate content of three iranian wheat cultivars

this study was carried out to determine the effect of fermentation, hydrothermal treatment, soda (na2co3), and table salt (nacl) addition on the extent of phytase activity and phytate degradation in three iranian wheat cultivars, namely, mahdavi, ghods, and roshan. the samples were milled to three different extraction rates, i.e. whole, 85%, and 75% flours and three kinds of leavening procedure (fermented, soda, and control), and four nacl percentages (0.0, 0.5, 1.0, 1.5%) were used for preparing dough in three replications. to evaluate the effect of heat treatment on phytic acid breakdown, baking was also done. the results indicated that among the wheat varieties, mahdavi had the highest level of phytase activity and phytic acid content followed by ghods and roshan; in which‚ most of the phytate was concentrated in bran fractions. fermentation (1% yeast at 37ºc for 3 hours), hydrothermal treatment (ph 4.8 at 55ºc for 12 hours) and salt addition (0 to 1.5%) to the dough samples resulted in an increased phytase activity, whereas soda addition (1%) decreased the enzyme activity. heat treatment reduced phytic acid content significantly.