Legal Question in Real Estate Law in California

Probably not, particularly if there is a bona fide dispute about the money owed. Generally, a person cannot take as collateral property which was not originally offered as collateral, especially in the absence of a formal security agreement between the parties. There are some exceptions, but they are unlikely to apply in a mother-daughter situation.

This is an example of "two wrongs don't make a right."

I should add that while you are legally entitled to have your things back pending a resolution of a genuine controversy over the money, things would be a bit different if there were no bona fide dispute over the money owed, because a court would probably refuse to get involved on your behalf until you paid your mother's undisputed claim.