A research on the changes in tea composition the different stages of black tea production

This study aims to determine several quality traits of classified black tea samples (BOP1A, BOP1A4, BOPF2), tea dusts (DUST0, DUST1), tea fibers and tea samples (before and after withering, SG-SÇ; before-after curling, KG-KÇ; after fermentation, FÇ; and after drying, KÇ) taken during the black tea production from fresh tea leaves grown in the Black Sea Region in our country. Moisture content of fresh tea leaves (YÇY) used in the black tea production was determined to be 76.19% and decreased to 6.97% at the end of the drying. Ash content of the leaves before and after withering (SG, SÇ), before and after curling (KG, KÇ) and after fermentation (FÇ) during the processing of fresh tea leaves into black tea was found to increase gradually and determined as 1.49-1.62%, 1.83-1.8% and 1.91% (g/g) based on the dry matter, respectively,. Total ash content of non-classified black tea sample (KRÇ) was identified to be 5.04% (g/g). Raw cellulose content of fresh tea leaves (FTL) was determined to be 5% whereas that of dried black tea was 14.49%. Although there seemed to be no considerable change in the caffeine content from outlet of withering to the fermentation exit, a slight increase (0.53- 0.58%) in caffeine was observed during the black tea production. Theaflavin/Thearubigin (TF/TR) ratios in classified black tea samples were found to be 2.60%, 3.60% and 3.10% depending on the size of tea leaves (BOP1A, BOP1A4, BOPF2), respectively. Theaflavin/ Thearubigin (TF/TR) ratios of tea dusts (DUST0, DUST1) were however determined to be 3.20% and 4.70% respectively. The characteristics of the black tea samples obtained were generally in compliance with the Tea Bulletin of the Turkish Food Codex (No: 2015/30)