Another thing that I forgot at the time I posted the information about zyme and azyme, (Yeast and non yeast breads) is that prior to the Western Churches using only unleavened bread, both were used in West and East. The change over to only unleavened bread in the West came about later. While it was always held that both were valid for use in the Eucharist, it became a bone of contention amone some Orthodox later.
There are a number of things like the bread having or not having yeast that were picked at as differences, that became blown out of proportion after the 1054 Schism. Just like crazy accusations that it was the Catholic Church who “Sold Indulgences” rather than individuals like Tetzel who were later repremanded for doing something contrary to Catholic practice. Levening or not was a non-issue that became an issue only after the Schism.
The Western Church holds zyme and azyme to both be valid. In the west it is only licit, (Legal) to use unlevened bread, without special permission. If a priest used leavening in the bread, in the West it would be an illegal act against church law, but not God’s law, so the Eucharist would be present. The Eucharist confected by bread that has or does not have yeast is the same, it is Jesus’ Body and Blood. Each drop and crumb the same as the other. At no time after the consecration and before the bread stops having the appearence of bread is one host or portion of the yeast bread any less Jesus than any other consecrated bread.