Comparative Study and Partial Characterization of Azorean Green Tea Polyphenols

Tea is grown in about 30 countries, including Azores Islands, and is the most widely consumed beverage worldwide. Green tea polyphenols (GTP) are the major water-soluble components in a cup of tea (Camellia sinensis (L.) O. Kuntze). The content of the Azorean GTP was determined by RP-HPLC with UV detection and compared with that of different origin samples. The Azorean GTP extraction yield was also determined using different extraction times from 10 to 60 min at 70°C, and also at different temperatures from 50 to 100°C, at a constant extraction time of 40 min. Quantitative determination of the total epicatechin derivatives and epigallocatechin gallate (EGCG) of different green teas were also compared with that of Azorean green tea. The EGCG:caffeine ratio was high in Azorean green tea as compared with others, which suggested a good source of a chemopreventive agent. The aroma of different green tea samples were compared using the SPME/GC-headspace methodology.