title: Protein distribution in commercial wet- and dry-milled corn germ.
abstract: To identify high-valued coproducts from commercially processed corn germ, it was necessary to determine the effect of processing conditions on corn germ proteins. We found that significantly less protein was extracted from commercial wet-milled as compared to dry-milled corn germ using Tris, sodium dodecyl sulfate (SDS) buffer containing 14 mM 2-mercaptoethanol at 100 degrees C for 10 min. SDS-polyacrylamide gel electrophoresis (PAGE) revealed a number of proteins with molecular masses ranging from approximately 10 to 66 kDa for the dry-milled corn germ as compared to only a few significant protein bands centered around 23 kDa in the wet-milled corn germ. The protein content of the wet- and dry-milled corn germ was approximately the same; however, nonprotein nitrogen values were significantly greater for the wet-milled than for the dry-milled germ. The distribution of fractionated germ protein freshly excised from the embryo of yellow dent corn kernels was more similar to that of dry-milled than wet-milled corn. SDS-PAGE of laboratory preparations of wet-milled corn germ more closely resembled commercial dry- than wet-milled corn germ, which could be attributed to limited microbial growth during steeping in the laboratory preparations.
authors.affiliation: Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA. nparris@errc.ars.usda.gov
authors.forename: Nicholas
authors.initials: N
authors.lastname: Parris
authors.forename: Robert A
authors.initials: RA
authors.lastname: Moreau
authors.forename: David B
authors.initials: DB
authors.lastname: Johnston
authors.forename: Vijay
authors.initials: V
authors.lastname: Singh
authors.forename: Leland C
authors.initials: LC
authors.lastname: Dickey
mesh_terms: D000383:Agriculture / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D005511:Food Handling / Q000379:methods; D009584:Nitrogen / Q000032:analysis; D010940:Plant Proteins / Q000032:analysis*; D012639:Seeds / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D010940:Plant Proteins; D009584:Nitrogen