I don't know mac the ripper but can't you select the demux option when ripping the dvd like this:
"You can also choose to demux the individual streams (.m2v, .ac3, .dts, .pcm, .spc) from the VOB, and select only the ones you want. To do this, click the "D" button (for demux), and then the "Streams" button to open the stream selection drawer. There, you can choose exactly which streams you want extracted."