Abstract: 【Objective】The objective of this paper is to characterize the aggregation state structure of modified starch using the infrared spectrometry.【Method】For the 1300–800 cm-1 region, the FTIR spectra of modified starch were deconvoluted Voigt-type equations for all found peaks. The areas of deconvoluted peaks at approx. 1047, 1022 and 980 cm-1 were obtained and the surface ratio of 980/1022, 980/1047, (980+1047)/1022 and 980/(1022+1047) cm-1 were analyzed for the effect of modification on the starch crystalline structure. Then the result was compared with that of X-ray diffractometry.【Result】The results indicated that acetification induced a decrease of starch crystallinity and the crystal structure changed from A-type to V-type, but the cross-linking of POCl3 had little effect on the starch crystal structure.【Conclusion】The results suggest that the infrared spectrometry can characterize the chain structure of modified starch as well as the aggregation state structure for the agreement of the results of the X-ray diffractometry.

Key words: infrared spectrometry, starch, crystal structure