High-performance size-exclusion chromatography (HPSEC) and fluorophore-assisted carbohydrate electrophoresis (FACE) to describe the chain-length distribution of debranched starch

Chain-length (CL) distribution is an important feature of the 'fine structure' of starch molecules, which are comprised of amylose and amylopectin. The objective of the present work was to combine data for two methods to achieve a more comprehensive data set that would allow a fuller comparison of the CL distribution for different starches. Both high-performance size-exclusion chromatography (HPSEC) and fluorophore-assisted carbohydrate electrophoresis (FACE) were carried out on endosperm starch isolated from five maize genotypes. For the CL distribution in the range DP ≤ 50, data in the HPSEC chromatogram were transformed to the form of a FACE electrophoregram, in which the x-axis is DP and the y-axis is the number of chains. The two sets of data in this region were shown to be similar. We conclude that the data sets from HPSEC and FACE may be considered together to describe the CL distribution more completely than for either method alone. We further note that for DP 6-50, data from HPSEC may be transformed to allow a similar presentation as for that obtained by FACE, such that FACE analysis might not be required for comparison of CL distribution of different starches.