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Pretreatment of Wet-Milled Corn Fiber to Improve Recovery of Corn Fiber Oil and Phytosterols

¹Assistant professor, Department of Agricultural Engineering, University of Illinois, Urbana, IL 61801. ²Corresponding author. E-mail: vsingh@uiuc.edu. Phone: 217-333-9510. Fax: 217-244-0323. ³Research food technologist, lead scientist and research leader, USDA, Eastern Regional Research Center, Agricultural Research Service, 600 E. Mermaid Lane, Wyndmoor, PA 19038. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable. ⁴Research biochemical engineer and lead scientist, USDA, National Center for Agricultural Utilization Research, Agriculture Research Service, 1815 N. University Street, Peoria, IL.

The phytosterol-containing oil in the corn fiber (corn fiber oil) has potential use as a natural low-density lipoprotein (LDL) lowering nutraceutical but its low concentration (1–3%) makes it difficult and expensive to extract. Pretreatment of corn fiber with dilute acid or glucosidases removed nonlipid components of fiber, producing oil-enriched fractions that should be more amenable to efficient and inexpensive oil extraction. Acid, as well as enzymes, significantly increased the content of corn fiber oil and its phytosterol compounds by hydrolyzing (and removing) the starch and nonstarch (cell wall) polysaccharides from the wet-milled corn fiber. Dual treatment of the fiber with acid and enzyme greatly increased the concentrations of corn fiber oil and its phytosterol components, compared with acid or enzyme treatments alone. Depending on the treatment, the oil concentration in the residual solids increased from 0.3 to 10.8% (21–771% increase in conc.) and the total phytosterol concentration increased from 19.8 to 1256.2 mg/g of fiber (11–710% increase in conc.) compared with untreated fiber.