Abstract
Although tea catechins in green tea and green tea beverages must be stable to deliver good sensory quality and healthy benefits, they are always unstable during processing and storage. Ascorbic acid (AA) is often used to protect catechins in green tea beverages, and AA is easily oxidized to form dehydroascorbic acid (DHAA). However, the function of DHAA on the stability of catechins is not clear. The objective of this study was to determine the effects of DHAA on the stability of catechins and clarify the mechanism of effects by conducting a series of experiments that incubate DHAA with epigallocatechin gallate (EGCG) or catechins. Results showed that DHAA had a dual function on EGCG stability, protecting its stability by inhibiting hydrolysis and promoting EGCG consumption by forming ascorbyl adducts. DHAA also reacted with (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), and (−)-epigallocatechin (EGC) to form ascorbyl adducts, which destabilized them. After 9 h of reaction with DHAA, the depletion rates of EGCG, ECG, EC, and EGC were 30.08%, 22.78%, 21.45%, and 13.55%, respectively. The ability of DHAA to promote catechins depletion went from high to low: EGCG, ECG, EGC, and EC. The results are important for the processing and storage of tea and tea beverages, as well as the general exploration of synergistic functions of AA and catechins.
Highlights
Tea catechins in green tea and green tea beverages make important contributions to flavor quality and health functions
Classical negative ESI (Electrospray Ionization) mass spectra of gallic acid (GA), EGC, and epigallocatechin gallate (EGCG) are shown in Figure 1A to verify the reliability of the qualitative analysis
The ability of dehydroascorbic acid (DHAA) to trap catechins indicated that DHAA could promote the degradation of catechins of tea or tea beverages when stored
Summary
Tea catechins in green tea and green tea beverages make important contributions to flavor quality and health functions. Catechins belong to the group of flavanols and account for about 70% of the total amount of polyphenols [1,2]. EGCG accounts for 50%–80% of the total catechins, exhibiting a number of beneficial properties for human health, including antioxidant and anticarcinogenic activity [4,5], as well as anti-inflammatory [6,7] and antidiabetic properties [8]. The stability of tea catechins has attracted increased attention in recent years, especially EGCG. The addition of ascorbic acid (AA) to green tea beverages is often used to protect catechins’ stability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
