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Title: REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY OF OAT PROTEINS: APPLICATION TO CULTIVAR COMPARISON AND ANALYSIS OF THE EFFECT OF WET PROCESSING

Author
item LAPVETELAININ A - UNIV TURKU, FINLAND
item Bietz, Jerold
item Huebner, Floyd

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Most oats are used as livestock feed. Today, however, the good nutritional properties of oats, such as high protein, fat, and fiber contents, are arousing much interest in using oats for food. During wet processing of oats to starch, a high-protein (about 50%) byproduct is also produced. This byproduct can be used in foods. Because of this, we have studied how the chemical composition of oat protein is affected by wet processing. Oa proteins were dissolved in solutions containing salt, alcohol, and alkali. They were then analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC). RP-HPLC can identify varieties, and also shows how proteins interact and change during storage and processing. All RP-HPLC conditions used for analysis of these proteins were optimized to give the best, most meaningful separations. These conditions are applicable for analysis of all protein classes in oats and oat products, and should help promote increased food use of oats.

Technical Abstract: Analysis conditions were optimized to characterize oat proteins by reversed-phase high performance liquid chromatography (RP-HPLC). Salt-soluble, alcohol-soluble, and alkali-soluble protein fractions of oats were extracted with 1.0 M NaCl, 52% ethanol, and 1% sodium dodecyl sulfate (SDS) in 0.05M borate buffer (pH 10), respectively. Columns differed in separation performance. Best resolution was achieved with C4 or C18 columns. Separation of salt-soluble and alkali-soluble proteins improved by increasing the concentration of ion pairing reagent (trifluoroacetic acid). Adding SDS, however, did not improve resolution. Reducing protein disulfide bonds with dithiotreitol after extraction improved resolution of alkali-soluble components. Optimal separation temperatures differed by a few degrees for different protein fractions. RP-HPLC reproducibility was generally good, although 10 replicate extractions of alcohol-soluble fraction revealed some components that were not consistently present. These results emphasize the importance of thoroughly optimizing RP-HPLC analysis conditions for new proteins.