Rietveld-based quantitative phase analysis of B-type starch crystals subjected to ultrasound and hydrolysis processes

The functional properties of starch could be improved with structural tuning through a number of processing techniques, intensely explored in the past few years by several industries such as food, pharmacology, paper and cosmetics. The current work proposes a model for determining the crystallinity of B-type Starch based only on X-ray diffraction (XRD) and Rietveld refinement method (RM). A sample of food grade potato starch (described as B-type Starch) was submitted to structural modifications using high energy ultrasound followed by acid hydrolysis. The sample was thereby studied by powder XRD measurements and later refined using RM. Apparent crystallite sizes were found to be stable after ultrasound processing, while the crystallinity increased 10% after hydrolysis. Hence, this procedure provides an easy and alternative approach for estimating the crystallinity and the crystallite sizes of the starch sample.