Alkaline dissolution of starch facilitated by microwave heating for analysis by size-exclusion chromatography.
A rapid, straightforward starch dissolution method was developed to facilitate analysis of starch by size-exclusion chromatrography (SEC). Soft wheat starch was dispersed in 6 M urea and 1 M KOH and subjected to heating for 35, 45, or 60 s in a microwave oven as a potential means of starch dissolution. An increase in microwave heating time enhanced starch solubility but resulted in a steady decrease in amylopectin peak area and a consequent, artifactual increase in the amylose peak area due to molecular degradation. However, microwave heating for 35 s afforded a reasonable separation of starch fractions by SEC while minimizing molecular degradation of starch in comparison to a traditional starch dissolution procedure. This procedure provides a fast (<30 min), simple, and reproducible starch dissolution method for preparation of starches for SEC analysis and represents the first successful report of direct dissolution of granular starch via microwave heating.
Kim
Hyun-Seok
HS
Department of Food Science and Toxicology, University of Idaho, Post Office Box 442312, Moscow, Idaho 83844, USA.
Huber
Kerry C
KC
Higley
Jeremy S
JS
D002850:Chromatography, Gel; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides; D008872:Microwaves; D017680:Potassium Compounds; D012995:Solubility; D013213:Starch / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*; D014508:Urea
D006878:Hydroxides; D017680:Potassium Compounds; D014508:Urea; D013213:Starch; C029943:potassium hydroxide