Using chromatography and mass spectrometry to monitor isomerization of catechin in alkaline aqueous with thermal processing

Abstract

Polyphenols are associated with a wide range of physiological properties. Catechins are a class of polyphenolic flavonoids predominantly found in foods and beverages that are chemically unstable.This study investigated the effects of thermal processing and pH on the structural changes to catechins and examined how these effects impact the antioxidant capacity of these molecules. The results indicated the total phenolic contents of catechin were increased after alkalifying and ther- Practical applicationsHeating process and pH adjustment are used to meet hygienic requirements and maintain flavor during tea infusion processing in tea beverage manufacturing. Catechins account for the largest sum of polyphenols found in green tea. Basification and heating could catalyze the isomerization of catechin through an opened heterocyclic ring pathway. Catechin remains stable in acidic solutions during thermal processing, thus, avoiding changes of quality.

Nanoencapsulation of synergistic antioxidant fruit and vegetable concentrates and their stability during in vitro digestion

“…However, under simulated intestinal conditions, as the incubation time increased, the ORAC value and total phenolic content of the free BUCA rapidly decreased to approximately 5% and 33%, respectively, at 12 h. These results were similar to those reported by Pérez‐Vicente et al ., where the total polyphenol content of pomegranate juice was maintained at the initial level after exposure to simulated gastric fluids, while only 29% of these compounds remained after incubation in simulated intestinal fluids for 2 h . This occurs because polyphenols are chemically unstable in alkaline solutions due to the ionization of their phenolic groups …”

Effects of Blue-Light-Induced Free Radical Formation from Catechin Hydrate on the Inactivation of Acinetobacter baumannii, Including a Carbapenem-Resistant Strain

“…Tea infusions turning brown is an important factor influencing the shelf life of canned or PET-bottled tea drinks. In Taiwan, 2.4 million bottles of green tea beverages were abandoned, according to the Food and Drug Administration (2010), because of storage factors, which may result in the natural degradation of catechins [ 6 , 9 ]. Under blue light irradiation, the transparent solution of catechin became yellowish, as shown in Figure 2 , while irradiation with green and red lights led to insignificant changes [ 9 ].…”

“…Catechin and its relevant photoproducts were examined using HPLC analysis, as described previously [ 6 , 9 ]. In short, (A), or 290 μg/mL CHPB (pH 8) kept in the dark, was used as a standard.…”

“…Catechin is a flavan-3-ol with four phenolic hydroxyl groups, as shown in Figure 1 . It is stable in an acidic pH, but unstable in neutral or alkaline situations under high-temperature treatments [ 6 ]. The esterification condensation of catechin and bicarboxylic acid in alkaline solutions with increasing temperatures and a yellowing of the reaction solution have been reported [ 7 ].…”

“…The esterification condensation of catechin and bicarboxylic acid in alkaline solutions with increasing temperatures and a yellowing of the reaction solution have been reported [ 7 ]. Catechin in an alkaline solution causes the cleavage of the heterocyclic ring (ring C) of flavan-3-ols via the oxidation of the ether bond when heated [ 6 ].…”