Phytochemicals and Quality of Green and Black Teas from Different Clones of Tea Plant

Tea is a popular drink with refreshing and functional properties. Bud, 1ˢᵗ leaf, and 2ⁿᵈ leaf of five varieties of tea clones (Gumti Takda-78, Ambari, Chiniya, and Tinali, which are popular in tea plantation area of Nepal) were collected and used for preparing green and orthodox black tea to study antioxidant activity, phytochemicals profile, chemical content, and sensory parameters. One or two leaves were hand-plucked from each bush to get a sample of about 100 leaves and processed for green and orthodox black tea for different clones of tea plants. Phytochemicals, antioxidant activity, and caffeine content were found higher in bud followed by 1ˢᵗ leaf and 2ⁿᵈ leaf for all clones of tea plants. Both types of tea (green and black) from Gumti were significantly (p<0.05) higher having tannin content, flavonoid content, total polyphenol content, caffeine content, and IC₅₀ value of 49.15 and 36.23 (mg GAE/g dry extract), 358.9 and 350.4 (mg QE/g dry extract), 590.5 and 570 (mg GAE/g dry extract), 2.85 and 2.94%, and 45.15 & 51.88 μg/mL, respectively. Green and orthodox tea from Takda-78 was found higher in caffeine content and the least in Tinali for both types of tea. Moisture, water extract, total ash, acid-insoluble ash, and crude fiber content in tea (green and black) from Gumti were found to be 5.4% & 5.37%, 65.89% & 71.46%, 5.524% & 6.52%, 0.46% & 0.57%, and 7.96% & 10.27%, respectively. The ratio of theaflavin and thearubigin (TF : TR) was found 1 : 8.61, 1 : 9.36, 1 : 9.70, 1 : 12.87, and 1 : 6.36 in Takda-78, Ambari, Gumti, Chiniya, and Tinali respectively. The total quality score in green tea (85.13%) and black tea (85.78%) from Gumti was significantly higher than others. Phytochemicals and antioxidant properties of green tea were significantly (p<0.05) higher than those of orthodox black tea for all clones of tea plant. This study suggests Gumti variety to be used in green and orthodox black tea processing for higher phytochemical, chemical, sensory quality, and antioxidant activity.