hey, your 'white' marshmallows look a little more pink than usual, try using a different white-balance, or adjusting the hues in an editing program. i like this idea though, but im not sure the textures add to the effect. I dun know if those are old, left out too long, or just that's what they look like in macro. But good effort!
Like the lighting, and love how you cropped it. There's a problem with the white marshmallows, though...they're pink. I don't know if this will help you or not because I haven't totally read it, but there is a tutorial on site on how to remove color casts in images. Might prove useful.
Awsome idea!!! I love how there is no backrop setup, the whiteness of the shot is all with actual objects. I'm not sure if others will like this as much as I do, but I have to give this a 10.