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Analysis of the oxidative degradation of proanthocyanidins under basic conditions.
J Agric Food Chem. 2004 Apr 21; 52(8):2292-6.JA

Abstract

Proanthocyanidin isolates from grape (Vitis vinifera L. cv. Pinot noir) skin and seed underwent oxidative degradation in solution (10 g/L) under basic conditions while exposed to atmospheric oxygen. Degradation was monitored by reversed-phase HPLC following acid-catalyzed cleavage in the presence of excess phloroglucinol (phloroglucinolysis) and by high-performance gel permeation chromatography. All isolates degraded under these conditions and followed second-order kinetics for over 1 half-life, consistent with an oxidation reaction. The conversion of proanthocyanidins to known subunits (conversion yield) when measured by phloroglucinolysis showed a dramatic decline over the course of the reaction. With the exception of (+)-catechin extension subunits, all individual subunits decreased in concentration during the oxidation process, also following second-order kinetics for over 1 half-life. Skin proanthocyanidins degraded the fastest due to the presence of (-)-epigallocatechin extension subunits. Seed procyanidins were degraded with and without flavan-3-ol monomers. Flavan-3-ol monomers slowed the rate of seed procyanidin degradation. The mean degree of polymerization (mDP) determined by phloroglucinolysis indicated a large decrease in mDP as the reaction progressed; yet, by GPC, the size distribution of all proanthocyanidins changed little in comparison. The conversion yield could be an important parameter to follow when using phloroglucinolysis as a means for determining proanthocyanidin mDP, and when monitoring the oxidative degradation of proanthocyanidins.

Authors+Show Affiliations

Department of Food Science and Technology, Oregon State University, Corvallis, Oregon 97331, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15080635

Citation

Jorgensen, Emily M., et al. "Analysis of the Oxidative Degradation of Proanthocyanidins Under Basic Conditions." Journal of Agricultural and Food Chemistry, vol. 52, no. 8, 2004, pp. 2292-6.
Jorgensen EM, Marin AB, Kennedy JA. Analysis of the oxidative degradation of proanthocyanidins under basic conditions. J Agric Food Chem. 2004;52(8):2292-6.
Jorgensen, E. M., Marin, A. B., & Kennedy, J. A. (2004). Analysis of the oxidative degradation of proanthocyanidins under basic conditions. Journal of Agricultural and Food Chemistry, 52(8), 2292-6.
Jorgensen EM, Marin AB, Kennedy JA. Analysis of the Oxidative Degradation of Proanthocyanidins Under Basic Conditions. J Agric Food Chem. 2004 Apr 21;52(8):2292-6. PubMed PMID: 15080635.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Analysis of the oxidative degradation of proanthocyanidins under basic conditions. AU - Jorgensen,Emily M, AU - Marin,Anna B, AU - Kennedy,James A, PY - 2004/4/15/pubmed PY - 2004/5/20/medline PY - 2004/4/15/entrez SP - 2292 EP - 6 JF - Journal of agricultural and food chemistry JO - J Agric Food Chem VL - 52 IS - 8 N2 - Proanthocyanidin isolates from grape (Vitis vinifera L. cv. Pinot noir) skin and seed underwent oxidative degradation in solution (10 g/L) under basic conditions while exposed to atmospheric oxygen. Degradation was monitored by reversed-phase HPLC following acid-catalyzed cleavage in the presence of excess phloroglucinol (phloroglucinolysis) and by high-performance gel permeation chromatography. All isolates degraded under these conditions and followed second-order kinetics for over 1 half-life, consistent with an oxidation reaction. The conversion of proanthocyanidins to known subunits (conversion yield) when measured by phloroglucinolysis showed a dramatic decline over the course of the reaction. With the exception of (+)-catechin extension subunits, all individual subunits decreased in concentration during the oxidation process, also following second-order kinetics for over 1 half-life. Skin proanthocyanidins degraded the fastest due to the presence of (-)-epigallocatechin extension subunits. Seed procyanidins were degraded with and without flavan-3-ol monomers. Flavan-3-ol monomers slowed the rate of seed procyanidin degradation. The mean degree of polymerization (mDP) determined by phloroglucinolysis indicated a large decrease in mDP as the reaction progressed; yet, by GPC, the size distribution of all proanthocyanidins changed little in comparison. The conversion yield could be an important parameter to follow when using phloroglucinolysis as a means for determining proanthocyanidin mDP, and when monitoring the oxidative degradation of proanthocyanidins. SN - 0021-8561 UR - https://www.unboundmedicine.com/medline/citation/15080635/Analysis_of_the_oxidative_degradation_of_proanthocyanidins_under_basic_conditions_ DB - PRIME DP - Unbound Medicine ER -