X-ray patterns were obtained with a D/Max-2200 X-ray diffractometer (Rigaku Denki Co., Tokyo, Japan). Starch samples were equilibrated in a saturated relative humidity chamber for 24 h at ambient temperature. The samples were scanned in the range of a scanning rate of 4 _/min. Relative crystallinity was calculated as the ratio of the areas of crystalline and amorphous regions of X-ray diffractograms