Analysis of proanthocyanidins in almond blanch water by HPLC-ESI-QqQ-MS/MS and MALDI-TOF/TOF MS

Almond seeds contain low molecular weight phenolics and larger polyphenols of the proanthocyanidin (PA) family that may provide health benefits associated with antioxidant and other physiological effects. In the process of blanching, the seed coating is removed by hot water treatment and the resulting effluent (almond blanch water, ABW) is already a diluted extract with potential applications. By using a combination of mass spectrometry techniques, HPLC-ESI-QqQ-MS/MS and MALDI-TOF/TOF MS, we report here for the first time the PA composition of ABW up to decamers. Freeze-dried ABW contains about 322 mu g/g of oligomeric (2-4 units) PA relatively quantified as procyanidin B1 dimer equivalents. We show that the PA present in ABW include monogalloylated and probably polygalloylated species apart from the procyanidins, prodelphinidins and propelargonidins previously reported in the seeds. ABW is a byproduct from almond processing that can be considered a source of oligomeric PA with potential applications as a dietary and functional ingredient. (C) 2012 Elsevier Ltd. All rights reserved.