according to this site, these photographs show the difference:
Proof that there is a difference.. at least according to this site: it is all in the chromatogram!
(note.. I know nothing about chromatograms, but.. maybe someone here does)
http://en.wikipedia.org/wiki/Chromatography
http://en.wikipedia.org/wiki/Thin_layer_chromatography
Vitamin C - Ascorbic Acid (left) / Acerola (right)