Improved methods for the structural analysis of the amylose-rich fraction from rice flour.

Cooking and sensory properties of rice are largely determined by the amylose content and structure. For relationships between functional and structural properties, a more accurate method to determine the structure of amylose is required. Here we calibrate size exclusion chromatography (SEC) columns, using Mark-Houwink parameters for linear starch and pullulan standards, to obtain the true molecular weight distribution of linear starch.

Measurement of the molecular weight distribution of debranched starch.

Combining molecular weight distribution (MWD) data for linear chains of debranched starch from capillary electrophoresis and from size exclusion chromatography (SEC) with detection by differential refractive index and by multi-angle laser light scattering has enabled Mark-Houwink parameters to be determined for linear starch chains. For accurate results, it was found to be important to take SEC band broadening into account, and a methodology for implementing this is presented. This deconvolution technique can be used to reveal features such as maxima or shoulders in the MWD which have qualitative as well as quantitative significance.