Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 16, 2006
Publication Date: January 15, 2007
Citation: Yadav, M.P., Moreau, R.A., Hicks, K.B. 2007. Phenolic acids, lipids, and proteins associated with purified corn fiber arabinoxylans. Journal of Agricultural and Food Chemistry, 55, p.943-947. Interpretive Summary: Previous studies in our lab have reported a method to produce a potentially useful food additive called Corn Fiber Gum (CFG). In this case, the word “gum” does not mean that this material would be used as a chewing “gum”, but rather as a food ingredient composed of complex carbohydrates that can serve as an emulsifier. This is a common use of the term “gum” in the food industry. This useful gum was made in our lab from corn fiber, a low-value by product of the industrial wet milling of corn. CFG was shown to be a better emulsifier than gum Arabic, a “gold standard” emulsifier, and was shown to have several other potential industrial applications. Previous studies indicated that CFG was a pure carbohydrate called an arabinoxylan that was free of other chemical groups that could alter its functional properties. However, it is unusual that a pure carbohydrate could serve as such a good emulsifier since emulsifiers usually have fat or proteins associated with them. In this current study we found for the first time, that in addition to arabinoxylan, purified CFG also contains three other chemical components that may contribute to its unique functional properties. These unique components include phenolic acids, lipids, and proteins. The discovery of the presence of these compounds in Corn Fiber Gum will have a great impact on the food industry, because it will provide a better understanding of the functional properties of Corn Fiber Gum. It will also provide opportunities to control the levels of these components to change the functional properties of Corn Fiber Gum and perhaps create modified products with enhanced functional value for specific applications.
Technical Abstract: Corn fiber gum (CFG) is a hemicellulose (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 more 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 highly sensitive 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, from 2-5% by weight. The presence of these phenolic acids, lipids and protein in CFG may contribute to its excellent emulsification and other functional properties.