I found a way to rip the sprites without anti-aliasing, but it's actually more work than the regular method. The Game smoothens the outline of the sprites by applying an alpha mask to the character. After dumping the textures to the hard disk, there's a folder called "png_by_rgb_a" which also contains the alpha mask. The sprites are now on a black background, but if you subtract the alpha mask from the sprite, you will get a solid outline
Example:
Example: