A new corn fiber gum polysaccharide isolation process that preserves functional components

Corn fiber gum (CFG) is a hemicellulose (arabinoxylan)-enriched fraction obtained by the extraction of corn bran/fiber using a mild alkaline hydrogen peroxide process. The unique polysaccharide, CFG, with its low solution viscosity has been proposed as a stabilizer for oil-in-water emulsions. We have verified that in some model systems, CFG can out-perform the “gold standard” emulsifier, gum arabic. Our results have also shown that “pure” CFG fractions often contain considerable amounts of associated lipids, phenolic acids and proteins which contribute to its emulsifying properties. The extraction of CFG with alkaline hydrogen peroxide was investigated using different combinations of alkali concentration and time to identify the optimum extraction condition to retain its functional groups (protein, lipids and phenolic acids). The pure CFG prepared by this process was hydrolyzed with 1.5 N methanolic KOH at 70 °C for 1 h to release hydroxycinnamic acids (p-coumaric and ferulic) and lipids. The total lipid was extracted with chloroform/methanol, evaporated and quantified. The released phenolic acids were identified and quantified using HPLC with detection by both UV and evaporative light-scattering detection (ELSD). The protein content was determined by an AACC approved combustion method. The total lipids, phenolic acids and protein content in CFGs isolated with lower alkali concentration for a shorter time was comparatively higher than CFGs isolated with higher alkali concentration for a longer time. The presence of these phenolic acids, lipids and protein in CFG may contribute to its excellent emulsifying properties and may combine to give improved chemical, physical, and even nutritional properties. Understanding these critical structural elements required for optimal emulsification properties will allow future commercial producers of CFG to provide consistent quality and functionality in their products.