Examinando por Autor "Reed, J.D."

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MALDI-TOF mass spectrometry of oligomeric food polyphenols
(Universiti Putra Malaysia (Malasis), 2013) Madrigal-Carballo, Sergio; Rodriguez, G.; Jose-Roberto, Vega-Baudrit; Krueger, C.G.; Reed, J.D.
Abstract. Structural heterogeneity of polyphenols from cranberries, grape seed extracts, sorghum and pomegranate was characterized by MALDI-TOF MS. Polyphenolics were isolated by liquid chromatography and subjected to MALDI-TOF MS using trans-3-indoleacrylic acid as the matrix. Spectral analysis gave information on degree of polymerization, monomeric substitution, and the nature of intermolecular bonds. Cranberry polyflavan-3-ols had variation in interflavan bonds (A-type and B-type) and contained polyflavan-3-ols linked to anthocyanins through a CH3-CH bridge. Polygalloyl-polyflavan-3-ols in grape seed extract had large variation in the degree of galloyl substitution. Sorghum polyflavans had structural heterogeneity in glycosylation and hydroxylation. Pomegranate hydrolyzable tannins were detected that correspond to previously described structures, such as punicalagin, but others that correspond to oligomeric ellgitannins in which two to five core glucose units are cross linked by dehydrodigalloyl and or valoneoyl units. Results demonstrate that large heterogeneity occurs in degree of polymerization, intermolecular bonds, pattern of hydroxylation, and substitution with monosaccharides and gallic acid.