Beamer title font color

The command \usebeamercolor[fg]{title in head/foot} (see p. 186 http://www.tex.ac.uk/CTAN/macros/latex/contrib/beamer/doc/beameruserguide.pdf) should provide you with the (text) color used in the header, even if you later decide to change your theme or change the title text color yourself in the preamble.

You can copy the color from the frame title this way:

\caption*{\usebeamercolor[fg]{frametitle}{My table}}