Abstract: Examinations were made on different fat－bloom extent of CTCBE chocolate.During different periods of stimulating fat－bloom in an artifical－climate chamber by using XRD,the results showed that there was closed relationship between polymorphic transition rate and fat－bloom.The faster the rate,the more serious the fat－bloom.In the early stimulating Period within (in 5 days),no fat－bloom was seen in any of the chocolate,and there showed the same crystal.However,in the later stimulating period (the 45th day),fat－bloom Could be found in all of the chocolates,but the extent of fat－bloom varied from CC,TC and LC.CC was the most serious one,TC next to CC,and LC next to TC,the XRD spectra showed the same result.In the middle of stimulating (the 20th day),the CC instead of LC and TC was the only one which showed fat－bloom,The erystal in CC was sharply different from that in TC andLC whereas LC and TC showed the same crystal in their XRD spectra.

Key words: Chocolate Polymorphic－transition Fat－bloom