Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/9/2008
Publication Date: 5/20/2008
Citation: Yadav, M.P., Parris, N., Johnston, D., Hicks, K.B. 2008. Fractionation, characterization and study of emulsifying properties of corn fiber gum. Journal of Agriculture and Food Chemistry. 56, p.4181-4187. Interpretive Summary: Corn Fiber Gum (CFG) is a potential alternative to imported gum Arabic, a flavor stabilizer, which is expensive and is often in short supply due to political and environmental issues in the African countries of origin. It is a potential high-valued coproduct of corn wet milling and biofuel production. Corn fiber gum is not one specific polysaccharide molecule but is made up of a mixture of polysaccharides with slightly different structures. In this study we fractionated CFG into several different fractions to evaluate the ability of the different fractions to stabilize flavors. We hoped to find one or more fraction that might contain CFG polysaccharides that have extremely high and consistent ability to stabilize flavors. This would be important since commercial manufacturers of CFG have had problems with product performance and consistency. We found that some of the fractionated components were poorer flavor stabilizers for soft drinks than the unfractionated whole CFG. One of the fractions was almost as good as the original mixture. These findings will help manufacturers to modify CFG manufacturing techniques so that CFG mixtures contain less of the inactive forms and more of the active ones. The findings will also aid the US soft drink industry if high quality commercial CFG becomes available for domestic soft drink manufacturing. Finally, if CFG becomes an item of commerce, corn processors will benefit from turning a low value byproduct into a valuable coproduct.
Technical Abstract: Corn fiber gum has been fractionated by hydrophobic interaction chromatography on Amberlite XAD-1180 resin using ionic, acidic, basic and hydrophobic solvents of different polarity. Characterization, including determination of total carbohydrate, acidic sugar and protein content has been done for each fraction together with measurements of molar mass, polydispersity, radius of gyration, Mark-Houwink exponent and intrinsic viscosity using multi-angle laser light scattering and online viscosity measurements. Emulsification properties of all fractions in an oil-in-water emulsion system with 20:1 oil to gum ratio was studied by measuring turbidity over 14 days. The results indicate that corn fiber gum consists of different components differing in their molecular weights, carbohydrate and protein contents. The main fraction eluted with NaCl, though low in protein content has the highest average molecular weight and was determined to be a better emulsifier than the other fractions. The unfractionated CFG which contains different molecular species is the best emulsifier.