Abstract: In this work, we study the effect of some instrumental parameters such as diffraction angle, step-length and scanning rate on the X-ray diffraction (XRD) analysis of starch. Meanwhile, the calculation of starch crystallinity was achieved using MDI Jade software by two different methods. Under the following conditions: diffraction angle of 4° to 60°, step-length of 0.02°and scanning rate of 10°/ min, satisfying test results were attained. The subjective factors affecting the calculation of starch crystallinit could be attenuated by selecting a diffraction angle between 4° and 30°. As a result, the calculation of starch crystallinity will be characterized by simplicity, rapidity and reliability. The relative starch crystallinity of corn, potato, and cassava was determined as 26.7%, 18.4% and 26.5%, respectively.

Key words: starch, crystallinity, MDI Jade software, calculation, novel method