Molecular characteristics of native sago starch and isolated fractions determined using asymmetrical flow field‐flow fractionation

The apparent average molar masses (M_w,app), apparent average radii of gyration (R_g,app), of native sago starch and fractions were determined using asymmetrical flow field‐flow fractionation coupled with multi‐angle light scattering and refractive index detectors (AF4/MALS/RI). Amylose‐type (Fraction A) and amylopectin‐type (Fraction B) were chemically separated from native sago starch. Native sago starch and Fractions (A–B) were dissolved in 1M 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 native sago starch and Fractions (A–B) were investigated. The average M_w,app values of native sago starch, Fraction (A) and Fraction (B) were 60 × 10⁶, 1.5 × 10⁶ and 60 × 10⁶ g/mol, respectively, with average R_g,app values of 142, 75 and 127 nm, respectively. The sphere‐equivalent hydrodynamic radii (R_h) values for native sago starch and fractions were determined from AF4 experimental parameters.