48KHz is usually associated with Digital Audio Tape - DAT.
You probably won't hear the difference between 44.1KHz & 48KHz. Apart from the very slightly extended frequency reproduction.
But quality doesn't come into it to be honest because you can have a DVD - 96KHz/24Bit audio - and have a crappy recording on it. The fact that its on a DVD won't improve the quality. With sampling frequencies above 44.1KHz the important factor is the 'Bit' rate or the 'sample resolution'.