Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/7/2006
Publication Date: 3/31/2007
Citation: Yadav, M.P., Fishman, M.L., Chau, H.K., Johnston, D., Hicks, K.B. 2007. Molecular characteristics of corn fiber gum and their influence on its emulsifying properties. Cereal Chemistry Vol. 84, No. 2, p.175-180. Interpretive Summary: The need to increase the value of by-products from corn milling has prompted us to investigate the ability of corn fiber gum (CFG) to serve as a valuable food emulsifier for stabilizing flavor oil droplets typically found in soft drinks. We have found that CFGs prepared from different corn milling processes differ in their molecular size, shape and compactness. CFGs which are bigger in size and more compact are better flavor stabilizers than those which are smaller in size and less compact. These findings will aid U.S. corn processors to produce CFGs which could be used as stabilizers in the flavor industry and thus increase the value of residues from corn milling.
Technical Abstract: 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 their emulsifying properties. CFG-1 and 2 fractions were isolated from different corn fiber sources by (a) a sequential alkaline extraction (0.1M NaOH and 0.05M Ca (OH)2) and H2O2 (0.1g/g fiber) bleaching to produce CFG-1 and (b) additional H2O2 (0.1g/g fiber) treatment of the alkali extracted residue at pH 11.5, yielding CFG-2. Multi-angle laser light scattering and online viscosity measurements were used to study molar mass, polydispersity, structure compactness and intrinsic viscosity of the generated CFGs. 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 (Mw), polydispersity (Mw/Mn), structure compactness and lower in solution weight-average intrinsic viscosity (nw) than the corresponding CFG-1. Their average Mw and intrinsic viscosities (nw) ranged from 244 to 491 kDa and 1.35 and 1.84 dL/g respectively. It was found that the emulsion stabilizing capacity of CFG-2 from each fiber source was superior to the corresponding CFG-1.