Effect of interaction of epigallocatechin gallate and flavonols on color alteration of simulative green tea infusion after thermal treatment

Abstract

Epigallocatechin gallate (EGCG) and flavonols are important phenolic compounds in green tea. These compounds are sensitive to thermal condition and their structural alteration results in making browning the green tea infusion. This study aimed to research the interaction between EGCG and flavonols during thermal infusion. EGCG and flavonols model solutions were prepared based on concentration in green tea infusion, and their colors appearance and attributes were analyzed in 10 h by thermal treatment. Results showed that kaempferol, quercetin, and myricetin accelerated the oxidation of EGCG and made the model solution browning. HPLC analysis revealed there was an obvious shift of a broaden peak in the mixed model solution of EGCG and flavonols after thermal treatment. This broaden peak was further purified on HPLC and solid phase extraction methods to yield colored complexes. The complexes showed the maximal absorption around 424, 442, and 482 nm. MS/MS analysis revealed that the complexes possessed of three components those were consisted of the interaction between EGCG and myricetin. These results indicated that the interaction between EGCG and flavonols might form complexes during thermal treatment, The complexes were contributed to make green tea infusion browning.

Mechanisms of Phytonutrient Modulation of Cyclooxygenase-2 (COX-2) and Inflammation Related to Cancer

“…), mode of propagation or even how the natural product is prepared and consumed. For example, it was shown that interaction between EGCG and flavonols of green tea might form complexes during thermal treatment (19) and that the temperature of green tea when consumed, affects the risk of gastric cancer (20). Most studies that are limited to a relatively small range of phytonutrients such as carotenoids or polyphenols may not allow researchers to identify associations between these phytonutrients and cancer due to the complexity, breadth, diversity and synergies of natural products present in food.…”

Variation of the Polyphenolic Composition and Antioxidant Capacity of Freshly Prepared Pomegranate Leaf Infusions over One-Day Storage

“…With the extension of storage at ambient conditions, the pH of PLI may decrease resulting from the carbon dioxide existing in the environment. Both flavonoids and their glycosides had been reported to endure polymerization under more acidic pH situations and then to form non-phenolic pigments, which causes the browning and deterioration of tea [ 24 ].…”

“…(ii) The amount of apigenin glycoside (31.98%, AG), luteolin glycoside I (35.9%, LG-I), and luteolin glycoside II (36.03%, LG-II) raised during 0–4 h and 6–8 h of storage, mostly coming from polymerization of flavonoids; whereas a reduction between 4 h to 6 h was observable likely due to hydrolysis of these polymers, partly conducive to the stability of TFs content during this storage period [ 6 , 24 ]. The ascent of flavonol glycoside (52.98%, FG) was continuous and comparatively higher within 24 h, possibly owing to more hydroxyl groups present in flavonols than that in flavones (apigenin and luteolin) [ 6 ].…”

Mixed Nectar of Cupuassu (<i>Theobroma</i><i> grandiflorum</i>) and Green Tea and the Effect of Preservatives and Storage on Nutritional and Sensorial Characteristics

“…The phenolic compounds content did not change (p>0.05) between the formulations. The Reference [31] reported that epigallocatechin gallate and flavonols are the main phenolic compounds in green tea, which are sensitive to thermal. Therefore, the similar content of the mixed nectar can be of the reduction of these phenolics during pasteurization.…”