Procyanidin Composition of Selected Fruits and Fruit Byproducts Is Affected by Extraction Method and Variety

Fruits and fruit byproducts are rich sources of polyphenols, including procyanidins, which are known to have numerous potential health benefits. This study investigated if varietal differences existed in the procyanidin composition of grape seed and if soaking in extraction solvent overnight prior to extraction improved the recovery of procyanidins from grape seed, grape pomace, and blueberry and cranberry powders. Riesling contained the highest amount of procyanidins, including the lower molecular weight monomers and dimers, followed by Chardonnay (60%), whereas Merlot contained much lower levels (14%) of individual and total procyanidins. A modified method of extraction whereby selected fruits and fruit byproducts were soaked in the extraction solvent overnight before the extraction process was begun increased procyanidins extracted by 24-100% from grape seeds and by 0-30% with berry procyanidin sources. The results indicate a wide variation in the procyanidin contents among different varieties of grape seeds that could have implications in the selection of procyanidin-rich germplasm. Soaking samples in the extraction solvent for 16 h resulted in increased procyanidins extracted and thus higher calculated concentrations in the food samples tested.