Characterisation of normal corn starch using asymmetrical flow field‐flow fractionation

Abstract

The apparent average molar masses (M w,app ), apparent average radii of gyration (R g,app ), diffusion co-efficients (D T ), and hydrodynamic radii (R h ) of normal corn (maize) starch and fractions were determined using asymmetrical flow field-flow fractionation coupled with multiangle light scattering and refractive index detectors (AF4/MALS/RI). AM-type (Fraction A) and AP-type (Fraction B) were chemically separated from normal corn starch. Normal corn starch and Fractions (A-B) were dissolved in 1 M KSCN using a high pressure microwave vessel. The effect of varying cross flow rates at a fixed channel flow rate upon the M w,app and R g,app distributions of normal corn starch and Fractions (A-B) were investigated. The average M w,app of normal corn starch, Fractions (A) and Fraction (B) were 41 Â 10 6 , 1.4 Â 10 6 and 39 Â 10 6 g/mol, respectively, with R g,app values of 129, 60 and 129 nm, respectively.

Separation and characterization of food macromolecules using field-flow fractionation: A review

“…The results from the AF4-MALS analyses were compared to capillary viscometry and increases in apparent densities were reflected in increases in the overlap concentration, c*. Recently, several papers with results for various starches utilizing AF4 have been reported (Juna & Huber, 2012a, 2012b, 2012cJuna, Williams, & Davies, 2011;Perez et al, 2011) including an extensive study of natural starches (Wahlund, Leeman, & Santacruz, 2011) and a comparison between AF4 and hydrodynamic/size exclusion chromatography (HDC-SEC) (Rolland-Sabaté et al, 2011).…”

Treatment of wx corn starch dispersions in a microwave reactor and their hydrodynamic properties determined using asymmetrical flow field‐flow fractionation

“…The reliable determination of the de‐facto molecular characteristics requires complete dissolution of starch–glucan materials 1–7. A detailed literature survey on the influence of various dissolution protocols and analytical techniques upon molar masses, radii of gyration and hydrodynamic radii ( R h ) values for wx corn starch (99% AMP) has been previously published 7.…”

“…Aggregation of the starch–glucan molecules in aqueous media is a dynamic process and is highly influenced by the inherent nature of the sample and the dissolution procedures employed 1–7. Furthermore, it is difficult to ascertain the degree of aggregation of starch solutions and dispersions.…”

“…Dissolution procedures employing a high pressure microwave vessel treatment (HPMV) 3–9 are rapid in comparison to other dissolution procedures such as autoclaving 10, 11 alkali/acid treatments 12 or use of organic solvents (particularly, DMSO) 12, 13 (Table 1). Some dissolution processes, such as HPMV, require a pre‐gelatinisation step to aid the disruption of the starch granules and improves the dispersion of the starch materials in aqueous media 3–9, 14 as shown in Table 1. However, domestic microwave instruments lack the ability to control and monitor the processing temperature inside the vessel.…”

The effect of long‐term alkali treatment on the molecular characteristics of native and extruded starches at 35°C

“…Many solvent systems were tested, such as alkali, acids, or DMSO for total dissolving of starch polysaccharides 1, 6–9.…”