Extraction and Quantitative Analysis of Oil from Commercial Corn Fiber

Abstract

Extraction of commercial corn fiber with hexane or supercritical CO 2 yielded an oil that comprised from 0.54 to 3.68 wt % of the fiber. An HPLC method with sensitive evaporative light-scattering detection (ELSD) was developed to analyze the lipid classes in corn fiber oil. Triacylglycerols were the most abundant lipid class, but the oil also contained sterol esters, free fatty acids, phytosterols, and very low levels of tocopherols. All fiber samples contained ferulate esters, similar in structure to “oryzanol”, a cholesterol-lowering substance found in rice bran and rice bran oil. Much more oil (up to 10-fold) and more ferulate esters (up to 2-fold) could be obtained from the fiber by grinding it before hexane extraction. The finer the fiber was ground, the more oil and ferulate esters were removed. Essentially all of the extractable oil and all of the ferulate esters were removed by extraction with hexane for 1 h at 25 °C. Keywords: Corn fiber; ferulate esters; ferulate-phytosterol esters; corn; Zea mays