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Browning of Epicatechin (EC) and Epigallocatechin (EGC) by Auto-Oxidation
- Source :
- Journal of Agricultural and Food Chemistry 68 (2020) 47, Journal of Agricultural and Food Chemistry, Journal of Agricultural and Food Chemistry, 68(47), 13879-13887
- Publication Year :
- 2020
-
Abstract
- Green tea catechins are well known for their health benefits. However, these compounds can easily be oxidized, resulting in brown color formation, even in the absence of active oxidative enzymes. Browning of catechin-rich beverages, such as green tea, during their shelf life is undesired. The mechanisms of auto-oxidation of catechins and the brown products formed are still largely unknown. Therefore, we studied auto-oxidative browning of epicatechin (EC) and epigallocatechin (EGC) in model systems. Products of EC and EGC auto-oxidation were analyzed by reversed-phase ultra-high-performance liquid chromatography with photodiode array detection coupled to mass spectrometry (RP-UHPLC-PDA-MS). In the EC model system, 11 δ-type dehydrodicatechins (DhC2s) and 18 δ-type dehydrotricatechins (DhC3s) that were related to browning could be tentatively identified by their MS2 signature fragments. In the EGC model system, auto-oxidation led to the formation of 13 dihydro-indene-carboxylic acid derivatives and 2 theaflagallins that were related to browning. Based on the products formed, we propose mechanisms for the auto-oxidative browning of EC and EGC. Furthermore, our results indicate that dimers and oligomers that possess a combination of an extended conjugated system, fused rings, and carbonyl groups are responsible for the brown color formation in the absence of oxidative enzymes.
- Subjects :
- 0106 biological sciences
tea
oxidation
Health benefits
Conjugated system
Mass spectrometry
Shelf life
01 natural sciences
Article
Catechin
Mass Spectrometry
Oxidative enzyme
Levensmiddelenchemie
discoloration
Browning
catechins
Chromatography, High Pressure Liquid
VLAG
Chromatography
Autoxidation
Food Chemistry
Chemistry
010401 analytical chemistry
General Chemistry
0104 chemical sciences
nonenzymatic
Brown color
General Agricultural and Biological Sciences
010606 plant biology & botany
Subjects
Details
- Language :
- English
- ISSN :
- 00218561
- Database :
- OpenAIRE
- Journal :
- Journal of Agricultural and Food Chemistry 68 (2020) 47, Journal of Agricultural and Food Chemistry, Journal of Agricultural and Food Chemistry, 68(47), 13879-13887
- Accession number :
- edsair.doi.dedup.....b8a9d45a27018168892189956e34402b