AOAC 2019 First Action Methods

AOAC Official Method 2019.05 Identification of A‐Type Proanthocyanidins in Cranberry‐Based Foods and Dietary Supplements Matrix‐Assisted Laser Desorption/Ionization Time‐of‐Flight Mass Spectrometry First Action 2019

A. Chemicals ( a ) Acetone and methanol were purchased from Fisher Scientific (Fair Lawn, NJ, USA). ( b ) Ethanol was obtained from Decon Laboratories Inc. (King of Prussia, PA, USA). ( c ) Sephadex LH-20 TM was obtained from GE Healthcare (Uppsala, Sweden). ( d ) Bradykinin, glucagon, 2,5-dihydrobenzoic acid (DHB), and cesium trifluoroacetate were purchased from Sigma-Aldrich (St. Louis, MO, USA). B. Samples ( a ) Thirty-five samples reported to contain A-type PAC were procured for this study. Cranberry fruit ( Vaccinium macrocarpon Aiton. Cv. “Scarlet Knight”, “BenLear A2”, “G1 A57”, “G2 A20”, and “Stevens A10”) was obtained from the Habelman Bros. Company (Tomah, WI, USA). Each cranberry fruit variety was harvested at 5 different stages of maturation. ( b ) Five commercially available cranberry products (nutritional supplements) were purchased from local markets. ( c ) Thirty-six samples reported to contain B-type PAC were also procured for this study. Apples ( Malus pumila Cv. “Cameo [PLU3066]”, “Honeycrisp [PLU3283]”, “Jazz [3293]”, “Ambrosia [3438]”, “SnapDragon [3442]”, “RubyFrost [PLU3443]”, “SweeTango [3603]”, “Kanzi [PLU3605]”, “Eve [PLU3607]”, “Kiku [3613]”, “Red Delicious [PLU4016]”, “McIntosh [4019]”, “Golden Delicious [PLU4020]”, “Braeburn [PLU4103]”, “Cripps Pink [PLU4128]”, “Pink Lady [PLU4130]”, “Fuji [PLU4131]”, “Gala [PLU4135]”, “Granny Smith [PLU4139]”, and “Paula Red [PLU4157]”), cocoa powders ( Theobroma cacao L.), and grape skins ( Vitis sp. ) “Cotton Candy [PLU3093]”, “Summer Royal [PLU4056]”, “Autumm King [PLU4498]”, “Crimson Seedless [PLU4499]”, “Thompson Seedless [94022]”, and “Flame Seedless [94023]”) were purchased from local markets between August and November 2018. The grapes were peeled to obtain the grape skins. ( d ) One sample of black chokeberry fruit ( Aronia melanocarpa Michx) was obtained from grower cooperator in WI. Fruit samples were frozen with liquid nitrogen, ground into a fine powder, and stored at -80 ° C until further use. C. Extraction of Proanthocyanidins The extraction of PAC was adapted from previous work. PACs were extracted from each sample (20 g) with acetone (70% v/v; 100 mL) in an ultrasonic bath for 15 min. The extract was centrifuged at 1800g