Insights to the Daf-

>>The KEREN ORAH explains that the Rambam learns this way because he rules that grain bought from a Nochri after its processing has been finished is exempt from Ma'aser, since it is "Laku'ach" (purchased grain). Once the law is that grain bought from a Nochri is exempt from Ma'aser, why is a special verse of "Degancha" needed to teach that grain finished in his possession is exempt from Ma'aser? It must be that the case of a Nochri who smoothes a pile of grain refers to a case in which he smoothes the grain of a Jew. The verse is teaching that even in such a case, where the grain belongs to a Jew, the grain is exempt from Ma'aser according to Torah law.

The Keren Orah, however, asks that this does not seem to be the intention of the Gemara. The Gemara later (67a) equates a Nochri's separating of Chalah from dough to his act of finishing the grain. No one says that when a Nochri kneads the dough of a Jew, the dough is exempt from Chalah. The SHULCHAN ARUCH (YD 330:1) rules that there is no Halachic relevance to who kneads the dough. Rather, the obligation of Chalah depends on who owns the dough. The Keren Orah also questions the Rambam's view from the Gemara earlier that discusses Miru'ach of Hekdesh, which obviously refers to grain that is in the possession of Hekdesh. Accordingly, "Miru'ach Oved Kochavim" also should refer to grain that is owned by a Nochri.<<

This point is raised by the Shitah Mekubetzes cited earlier in the Insight (#1) and answered.