I don't know if Blu-ray supports 48fps - is only 24fps version available?
"High-definition (1080-line) television is also interlaced—hence the 1080i designation. But 1080p high-definition movies are progressively drawn line after line—they're not interlaced. In fact, Blu-ray actually displays at 30 fps regardless of the source material. Using a method called 2:3 pulldown, it distributes the frames to display 24 fps film footage properly at 30 fps." -PC Mag (The Hobbit' at 48fps: Frame Rates Explained)