maxNumCompThreads(1) should still work. The documentation page for maxNumCompThreads indicates that maxNumCompThreads will be removed in a future version: http://www.mathworks.com/help/matlab/ref/maxnumcompthreads.html
Another option for setting the maximum number of computational threads to 1 is to use the -singleCompThread option when starting MATLAB® to limit MATLAB to a single computational thread. Open MATLAB from a terminal with
matlab -singleCompThread