Characterization of proanthocyanidins in grape seeds using electrospray mass spectrometry.
Two proanthocyanidin (PA) fractions, one (Sdp3) with the mean degree of polymerization (mDP) of 3 and the other (Sdp9) with mDP of 9, were obtained from a Vitis vinifera cv. Shiraz grape seed extract. The PA fractions were directly analyzed by electrospray ionization mass spectrometry (ES-MS) and negative ion mass spectra were recorded. The mass spectrum of Sdp3 exhibited only singly charged ions corresponding to the molecular mass of PA with a degree of polymerization (DP) up to 9 (nonamers). In contrast, Sdp9 yielded rather complex mass spectra featuring ions with single [M - H](-), double [M - 2H](2-) and triple [M - 3H](3-) charge representing the molecular masses of PAs up to a DP of 28. In addition, the degree of galloylation per procyanidin (DG) was observed to be up to 5 (pentagallates) in Sdp3 and 8 (octagallates) in the Sdp9. This is the first evidence obtained by mass spectrometry for the distribution of grape seed PAs with such a high degree of polymerization and a broad diversity of galloylation. ES-MS data together with the complementary information provided by acid hydrolysis provides a detailed picture of the composition of grape seed PAs.
Hayasaka
Yoji
Y
The Australian Wine Research Institute, PO Box 197, Glen Osmond, SA, 5064, Australia. Yoji.Hayasaka@awri.com.au
Waters
Elizabeth J
EJ
Cheynier
Véronique
V
Herderich
Markus J
MJ
Vidal
Stéphane
S
D000872:Anthocyanins / Q000032:analysis* / Q000737:chemistry*; D006868:Hydrolysis; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D044945:Proanthocyanidins; D012639:Seeds / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry*
D000872:Anthocyanins; D007477:Ions; D044945:Proanthocyanidins; C013221:proanthocyanidin