My understanding is that, as a general rule, the voting behavior of individual jurors is confidential, and must not be disclosed publicly.
Sometimes, individual jurors sitting on high-profile court cases will come out after the trial and explain how and why they voted the way they did, but to my understanding, it would not be permitted for anyone to be "outed" without their explicit permission.
I thus cannot imagine any large-scale study examining possible racial bias - unless they examine only all-White vs. all-Black juries.
Regards,
In that case the defendant was accused of holding up a liquor store. The defendant's lawyer made a pathetic attempt to argue that all black men look the same to white people because the guy at the register was white--but the prosecution's main witness was a black woman.