- Procyanidin A2 and Its Degradation Products in Raw, Fermented, and Roasted Cocoa
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Cocoa is known as an important source of flavan-3-ols, but their fate from the bean to the bar is not yet clear. Here, procyanidin A2 found in native cocoa beans (9-13 mg/kg) appeared partially epimerized into A2E1 through fermentation, whereas a second epimer (A2E2) emerged after roasting. At m/z 575, dehydrodiepicatechin A was revealed to be the major HPLC peak before fermentation, whereas F1, a marker of well-conducted fermentations, becomes the most intense after roasting. RP-HPLC-ESI(-)-HRMS/MS analysis performed on a procyanidin A2 model medium after 12 h at 90 °C revealed many more degradation products than those identified in fermented cocoa, including the last epimer of A2, A2 open structure intermediates (m/z 577), and oxidized A-type dimers (m/z 573).
- De Taeye, Cédric,Caullet, Gilles,Eyamo Evina, Victor Jos,Collin, Sonia
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p. 1715 - 1723
(2017/03/11)
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- Oligomeric flavanoids. Part W. Base-catalyzed pyran rearrangements of procyanidin B 2, and evidence for the oxidative transformation of B- to A-type procyanidins
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Procyanidin B-2 3 is subject to facile C-ring isomerizations in 0.1M NaHCO3 solution to form a novel series of 3,4,9, 10-tetrahydro-2H, 8-pyrano[2,3-h]chromenes 7, 9, and 10. The low percentage conversion of B- to A-type procyanidin 2 is rationalized in terms of an initial oxidative removal of hydride ion at C-2 (C-ring).
- Burger, Johann F. W.,Kolodziej, Herbert,Hemingway, Richard W.,Steynberg, Jan P.,Young, Desmond A.,Ferreira, Daneel
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p. 5733 - 5740
(2007/10/02)
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- Tannins and Related Compounds. LIX. Aesculitannins, Novel Proanthocyanidins with Doubly-Bonded Structures from Aesculus hippocastanum L.
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A chemical examination of the seed shells of Aesculus hyppocastanum L.has led to the isolation of proanthocyanidins A-6 (10) and A-7 (11), and aesculitannins A (12), B (13), C (14), D (15), E (16), F (17) and G (18).On the basis of chemical and spectroscopic evidence, proanthocyanidins A-6 (10) and A-7 (11) have been determined to be A-type dimers each possessing a C-4, C-6 interflavanoid linkage, while aesculitannins A (12), B (13), C (14), D (15), E (16), F (17) and G (18) have been characterized as oligomeric proanthocyanidins possessing A-type unit(s) in each molecule.In addition, the presence of (-)-epicatechin (1), proanthocyanidins B-5 (3), A-2 (4), A-4 (5) and C-1 (6), epicatechin-(4β->6)-epicatechin-(4β->6)-epicatechin (7), and cinnamtannins B1 (8) and B2 (9) was also demonstrated Keywords---Aesculus hippocastanum; Hippocastanaceae; aesculitannin; doubly-bonded proanthocyanidin; procyanidin; condensed tannin; flavan-3-ol; thiolytic degradation; epimerization; hydrogen peroxide oxidation
- Morimoto, Satoshi,Nonaka, Gen-ichiro,Nishioka, Itsuo
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p. 4717 - 4729
(2007/10/02)
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- Tannins and Related Compounds. L. Structures of Proanthocyanidin A-1 and Related Compounds
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The structures of proanthocyanidin A-1 (2) and two related proanthocyanidins, tentatively named A-4 (3) and A-5' (4), have been established unambiguously on the basis of spectroscopic evidence and chemical correlations with the structurally known proantho
- Nonaka, Gen-Ichiro,Morimoto, Satoshi,Kinjo, Jun-Ei,Nohara, Toshihiro,Nishioka, Itsuo
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p. 149 - 155
(2007/10/02)
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