Molecular characteristics of corn fiber gum and their influence on CFG emulsifying properties

The molecular characteristics of two purified arabinoxylan fractions derived from corn kernels, corn fiber gum-1 and -2 (CFG-1 and -2), have been studied and correlated with emulsifying properties. CFG-1 and -2 fractions were isolated from different corn fiber sources by 1) a sequential alkaline extraction and H2O2 bleaching to produce CFG-1; and 2) additional H2O2 treatment of the alkali-extracted residue at pH 11.5, yielding CFG-2. Multiangle laser light-scattering and online viscosity were used to measure the molar mass, polydispersity, structure compactness, and intrinsic viscosity of the generated CFG fractions. Emulsification properties in an oil-in-water emulsion system with 10:1 oil-to-gum ratio was investigated by measuring turbidity of an aliquot from the bottom of the diluted emulsion over 10 days. The isolated CFG-2 from each fiber source was higher in weight-average molar mass (M(w)) polydispersity (M(w)/M(n)) and structure compactness, and also lower in solution weight-average intrinsic viscosity (eta(w)) than the corresponding CFG-1. Average M(w) and eta(w) values were 244-491 kDa and 1.35-1.84 dL/g, respectively. The emulsion stabilizing capacity of CFG-2 from each fiber source was superior to the corresponding CFG-1.