MOLAR MASSES AND SIZES OF STARCHES BY HIGH-PERFORMANCE SIZE-EXCLUSIONCHROMATOGRAPHY WITH ONLINE MULTI-ANGLE LASER-LIGHT SCATTERING DETECTION

Starch was characterized for analysis by high-performance size-exclusi on chromatography (HPSEC) with detection by multiple-angle laser light -scattering and refractive index. Corn starches (amylopectin-to-amylos e ratios of 1:0, 3:1, 1:1, and 3:7), presolubilized potato starch, and potato starch granules were analyzed. For corn starches, analysis by HPSEC revealed that weight average molar mass (M(w)) and z-average roo t mean square radius of gyration (R(gz)) decreased with increasing per centage of amylose. For potato starches, granules had a much higher M( w) and R(gz) than presolubilized starch. All chromatograms were polymo dal in nature with at least two high M(w) amylopectin components. Exce pt for high amylose corn starch, R(gz) values from this study were com parable with results from an earlier HPSEC/viscometry study. The R(gz) values from microscopic studies were lower than from chromatographic studies.