Study On Phytate Degradation Of Steamed Bread With Different Leavened Ways

In order to investigate the degradation o f phytic acid in d ifferent puffedsteamed bread, the changed of nutrie nt co mposition, phytic ac id，HCL extractabilityof minerals，and phytase activity of the steamed breads were compared based on theinvestigatio n of nutrient composition and phytic acid content o f wheat meal inchina．And the nutrie nt absorption of steamed breads that produced by differentfermented methods was evaluated by anima l experiment. The ma in results were asfo llowing．（1）Wheat meals were collected from six areas in China．The nutrientcompos ition of wheat meals and the effect of different leavened ways to the whea-ten food（Sourdough, Yeast and Baking powder）were stud ied．The results showedthat the nutrie nt compos ition of wheat mea ls from different producing areas weredifferent．Different leavened ways has a significant impaction on the nutrientcompos ition．The contents of protein，VB1，VB2，Fe，Ca，Mg，Zn and K in wheatenfood that was fermented by yeast were highly increased．However，the increase ofsourdough and baking powder produced wheaten food was not apparent．（2）The content of phytic acid in wheaten food puffed by different ways（Sourdough、Yeast and Baking powder）were studied. The results showed that thecontent o f phytic acid in wheaten food that ferme nted by sourdough and yeast werereduced, and yeast was more effective than sourdough．However，baking powderinhib ited the degradation o f phytic acid．（3） Phytase activity of flour dough during yeast fermentation wasstudied．The results showed that phytate phosphorus in the dough could be hy-drolyzed only39.1%after180min witho ut yeast． However, hydrolyze rate ofphytate phosphorus raised to90.6%by adding yeast. The results ind icated thatyeast could improve the degradation of phytate phosphorus and increase the phy-tase activity of dough．（4）HCl-extractability of minerals of wheaten food that fermented by sour-dough and yeast were compared. Compared to the control group, fermentationcould influe nce the HCl-extractability of minerals in wheaten food（P<0.05）．HCl-extractability o f Ca， Mg， K， Zn increased significantly in the yeast group（P<0.05）．However，it was no obvious in the sourdough group．Moreover，thecontents o f minera ls and HCl-extractability o f minera ls increased during the fer-mentatio n of yeast． （5）The mice were fed with wheaten food that produced by yeast and sour-dough, the absorption and utilizatio n of the nutrient compos ition werestudied．The initia l body weight of mice was no significant differences，compare tothe control group，the fina l we ight of each experime nta l group has changed ob-vious ly（P<0.05）．The food utilization rate of the yeast group increased signif-icantly（P<0.05）．The total cholesterol content of the yeast group was slightlyhigher than the sourdough group（P<0.05）．However，the content of triglyceride andhigh dens ity lipoprotein cho lesterol was no s ignificant d ifference in the gro ups（P>0.05）．Moreover，the content of Ca in serum of the yeast group was higherthan other groups（P<0.05），the content of Mg，Zn content was little differencebetween group（sP<0.05）．According to the content of minerals in liver，the contentof Ca，Mg，Zn，K was no significant difference in the groups（P>0.05），but itwas higher tha n the control group（P<0.05）．...