The familiar Mac OS X dialog box will pop up, asking you where you’d like to put your exported file.

If you toggle the Format option near the bottom to Audio Only before you start the export, QuickTime will save just the audio out as an .m4a file, ready to be imported into iTunes.
Don’t miss the best of The Mac Observer
Set us as a preferred source and our Apple reporting ranks higher in your Google Search results and Discover feed — one tap, no account changes.

Or ready to be put anywhere else you like, really. You are the boss of your .m4a files, my friends.
Discussion