Quantification and Partial Characterization of the Residual Protein in Fully and Partially Refined Commercial Soybean Oils

A method has been developed to determine residual protein in refined oils, a potential trigger of allergic reactions. High-pH bicarbonate or borate buffers were found to be the most effective extractants, residual oil protein comprising a mixture of proteins of M r 6000−100000. Extracted protein cou...

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Bibliographic Details
Published in:Journal of agricultural and food chemistry 2011-03, Vol.59 (5), p.1752-1759
Main Authors: Rigby, Neil M, Sancho, Ana I, Salt, Louise J, Foxall, Rob, Taylor, Steve, Raczynski, Ana, Cochrane, Stella A, Crevel, Rene W. R, Mills, E. N. Clare
Format: Article
Language:English
Subjects:
amino acid composition
Amino Acids - analysis
Benzoates
Bicarbonates
Biological and medical sciences
Borates
buffers
Chemical Aspects of Food Safety
correlation
Fat industries
Food Handling
Food Hypersensitivity - immunology
Food industries
Fundamental and applied biological sciences. Psychology
oil refining
protein content
proteins
Quinolines
Reproducibility of Results
soybean oil
Soybean Oil - chemistry
Soybean Proteins - analysis
Soybean Proteins - immunology
soybeans
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Summary:A method has been developed to determine residual protein in refined oils, a potential trigger of allergic reactions. High-pH bicarbonate or borate buffers were found to be the most effective extractants, residual oil protein comprising a mixture of proteins of M r 6000−100000. Extracted protein could be quantified with superior precision using 3-(4-carboxybenzoyl)quinolone-2-carboxaldehyde (CBQCA). Residual protein content determined in a set of oils using the borate extraction−CBQCA assay was positively correlated with contents determined using a bicarbonate−total amino acid analysis method. Oil refining substantially reduced the oil protein content determined by the borate−CBQCA assay with neutralized/refined, bleached, and deodorized (fully refined) oils containing 62−265 ng/g oil, whereas crude un-degummed oils contained 86000−87900 ng/g of protein. These analyses and published data on cumulative threshold doses for soybean suggest that even the most sensitive individuals would need to consume at least 50 g of highly refined oil to experience subjective symptoms.
ISSN:0021-8561
1520-5118
DOI:10.1021/jf103560h