VALUE ADDED COPRODUCTS FOR IMPROVING THE ECONOMICS AND GREENHOUSE GAS EMISSIONS OF CORN AND CELLULOSIC FUEL ETHANOL PRODUCTION
Location: Sustainable Biofuels and Co-Products
Title: Contribution of lipids, phenolic acids, and protein rich components to emulsifying properties of corn fiber gum and acacia gum
Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: September 20, 2010
Publication Date: September 20, 2011
Citation: Yadav, M.P., Moreau, R.A., Johnston, D., Hicks, K.B. 2011. Contribution of lipids, phenolic acids, and protein rich components to emulsifying properties of corn fiber gum and acacia gum. In: Kennedy, J.F., Phillips, G.O., Williams, P.A., editors. World Conference on New developments in acacia gums research, products and processes, September 20-22, 2010, Cambridge, UK. published by Royal Society of Chemistry. 261-268.
Corn fiber gum (CFG) is an arabinoxylan enriched fraction obtained by the extraction of corn bran/fiber using a proprietary alkaline hydrogen peroxide process. When purified CFG prepared by this process was hydrolyzed with concentrated base (1.5 N methanolic KOH at 70 °C for one hour) considerable amounts (up to 0.015% by weight) of hydroxycinnamic acids (p-coumaric and ferulic) and lipids, were released. The released phenolic acids and lipids were identified and quantified using HPLC with detection by both UV and evaporative light-scattering detection (ELSD). During the wet milling of corn, two types of corn fiber are produced, coarse fiber which is primarily from pericarp, and fine fiber which is from the endosperm. The total phenolic acid content in CFGs purified from coarse corn fiber (pericarp fiber) is comparatively higher than that purified from fine corn fiber (endosperm fiber). It was also determined that the purified CFG samples contained significant amounts of strongly associated proteins (2-5% by weight). The well known emulsifier, gum arabic, which is a mixture of polysaccharides and arabinogalactan-proteins (AGPs) also, contains lipids. The present studies explore the hypothesis that these lipids are attached to the gum arabic AGPs as glycosyl-phosphatidylinositol (GPI) lipids, or in some other way, and make a significant contribution towards its emulsifying properties. Treatment of gum arabic either with nitrous acid or 50% aqueous HF at 0oC (which cleaves the GPI linker), decreased the emulsion stabilizing capacity of gum arabic. Thus it is concluded that presence of lipids and protein strongly associated or bound to CFG or gum arabic may contribute to their excellent ability to emulsify oil-in-water emulsions.