Studies on Preservation of Constituents in Canned Drinks Part III. Changes of Some Constituents during Processing of Canned Tea Drinks.

Suematsu, Shinichi; Hisanobu, Yoshihiro; Saigo, Hideaki; Matsuda, Ryoko; Hara, Kyoko; Komatsu, Yoshihiro

doi:10.3136/nskkk1962.40.181

Cited by 2 publications

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“…Many researchers have found that tea catechins could convert to their corresponding epimers in traditionally brewed tea infusion and canned tea drinks during brewing, production, and storage (8,(11)(12)(13)(14)(15)18). The epimerization of tea catechins depends strongly on pH and temperature.…”

Section: Discussionmentioning

confidence: 99%

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Stability of Tea Catechins in the Breadmaking Process

Wang

Zhou

2004

J. Agric. Food Chem.

162

106

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A green tea extract (GTE) was incorporated into bread as a source of tea catechins. The stability of tea catechins in the breadmaking process including unfrozen and frozen dough was studied. A method was developed for the separation and quantification of tea catechins in GTE, dough, and bread samples using a RP-HPLC system. The separation system consisted of a C18 reversed-phase column, a gradient elution system of water/methanol and formic acid, and a photodiode array UV detector. Tea catechins were detected at 275 nm. GTEs at 50, 100, and 150 mg per 100 g of flour were formulated. The results obtained showed that green tea catechins were relatively stable in dough during freezing and frozen storage at -20 degrees C for up to 9 weeks. There were no further detectable losses of tea catechins in bread during a storage of 4 days at room temperature. It was also revealed that (-)-epigallocatechin gallate (EGCG) and (-)-epigallocatechin (EGC) were more susceptible to degradation than (-)-epicatechin gallate (ECG) and (-)-epicatechin (EC). (-)-EGCG and (-)-ECG were normally selected as the quality indices of green tea catechins, and their retention levels in freshly baked bread were ca. 83 and 91%, respectively. One piece of bread (53 g) containing 150 mg of GTE/100 g of flour will provide 28 mg of tea catechins, which is approximately 35% of those infused from one green tea bag (2 g).

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Section: Discussionmentioning

confidence: 99%

“…Under acid condition (pH <4) tea catechins were stable, whereas they were relatively unstable in neutral or alkaline condition (pH >6). The stability of tea catechins was also subject to heating temperature (11,(13)(14)(15). A turning point temperature of 82 °C was found to vary the stability of tea catechins (11).…”

Section: Introductionmentioning

confidence: 99%