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Effect of Oil Extraction Method on Enzymatic Digestibility of Corn Germ Arabinoxylan
Author(s) -
Leathers Timothy D.,
Price Neil P. J.
Publication year - 2007
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cchem-84-3-0243
Subject(s) - product (mathematics) , agricultural science , agriculture , brand names , national standard , chemistry , business , mathematics , advertising , food science , environmental science , geography , geometry , archaeology
Corn (maize or Zea ma vs L.) residues are abundant renewable sources of lignocellulosic biomass. In a biorefinery concept, some of these materials will become substrates for conversion to fuels and chemicals (Johnson and May 2003). A variety of corn residues have been investigated as sources of fermentable sugars including corn fiber, bran, cobs, and stover. However, very little work has been reported on the utilization of defatted corn germ. More than one million tons of corn oil are produced annually in the United States, producing over a half million ton of defatted germ as a by-product (Ash and Dohlman 2006). Currently, this material is folded into relatively low-value animal feeds such as corn gluten feed (Johnson and May 2003). More than 90% of corn oil is produced by the wet-milling process that separates the germ from the kernel. The germ contains 4550% oil (Orthoefer et at 2003), which is extracted using solvents, expelling, or a combination of these methods. Defatted corn germ contains high-quality protein, arabinoxylan, residual starch, and cellulose (Lawton and Wilson 2003; Watson 2003). Hespell et at (1997) reported that purified arabinoxylan from corn germ is resistant to digestion by commercial enzymes. However, crude enzyme preparations from Aureobasidium sp. strain NRRL Y2311-1 were effective in producing monosaccharides from defatted corn germ (Leathers 2004). Moreover, defatted corn germ was more susceptible to enzymatic digestion than corn fiber (pericarp), even without chemical pretreatment (Leathers and Gupta 1996). It was suggested that the superior digestibility of corn germ arabinoxylan was either due to its chemical structure or that the oil extraction process itself served as an efficient pretreatment (Leathers 2004). To test this second possibility, whole unextracted corn germ and germ extracted by three different processes were compared for digestibility.