The new type bread yeast samples containing high quantity organic microelements such as Fe,Zn,Se and Cr were prepared through the biologic enrichment of bread yeast,which changed the inorganic Zn、Fe、Se and Cr into organic microelements.The cultivating conditions were determined.When wort was used as culture medium,sugar degree was 11BX,the inoculum of yeast was 10%,the culturing temperature was 28℃,and the culturing time was 48h,the best additive concentration of Zn was 150μg/mL,resulting in both of the content of total Zn and organic Zn in the yeast were the highest,which were 891.05 μg/g and 810.36 μg/g respectively.The best additive concentration of Fe was 150μg/mL,when both of the content of total Fe and organic Fe in the yeast were 2287.50μg/g and 2252.83μg/g respectively.The best additive concentration of Se was 20μg/mL,when the contents of total Se and organic Se in the yeast were 407.80μg/g and 398.50μg/g respectively.The best additive concentration of Cr was 20μg/mL,when the contents of total Cr and organic Cr in the yeast were the highest,which were 184.43μg/g and 134.86μg/g respectively.The grain size of the prepared bread yeast samples was about 300～400nm after ball milling for 15h,which can be absorbed and utilized more easily by bodies.
