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Molecular Characteristics of Corn Fiber Gum and Their Influence on CFG Emulsifying Properties

¹Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. ²Corresponding author. Phone: 215-836-3783. Fax: 215-233-6406. E-mail: madhav.yadav@ars.usda.gov

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 (η_w) than the corresponding CFG-1. Average M_w and η_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.