b - D - Fructofuranose a - D - Fructofuranose O HO OH CH2 OH HOCH2 OH O HO OH HOCH2 CH2 OH OH O OH CH2OH H OH OH OH CH2OH C HO C H H C OH H C OH O OH CH2OH H C H C OH C H H HO H C OH CH2OH O C Naturally-occurring free form Fructose (levulsoe)b - D - Fructofuranose a - D - Fructofuranose O HO OH CH2 OH HOCH2 OH O HO OH HOCH2 CH2 OH OH O OH CH2OH H OH OH OH CH2OH C HO C H H C OH H C OH O OH CH2OH H C H C OH C H H HO H C OH CH2OH O C Naturally-occurring free form Fructose (levulsoe)