1. Introduction  Green tea has become a very popular drink worldwide because of its health benefits attributed to high polyphenol (~30 %) and l-theanine content (~1-2 %).  Green tea extracts are usually spray dried and further processed into Ready-To- Drink (RTD) green tea beverages.  Response surface methodology was employed to optimize thermal extraction of green tea by controlling 3 key parameters namely, water-to-tea ratio (WTR), temperature and time. Important organoleptic characteristics concerned with quality of RTD beverage such as tea cream (%), colour of extract and turbidity were measured.  Chemical quality parameters were introduced for assessing green tea extracts Materials and Methods Conclusion  Made green tea (Tata Tea, India)  Extracts were prepared from green tea with 3 different WTR (30:1, 45:1, 60:1; v:w) over 3 extraction periods viz. 20, 40 and 60 min at 3 different temperatures of 70°C, 80°C and 90°C. Tea cream contents and turbidity were measured at beverage strength (0.29 % w/v). Analyses  Total soluble solids (TSS) and yield - Nagalakshmi et al., 1984  Total polyphenols - International Standard (ISO ⁄CD, 2005)  L-theanine - Chen et al., 2008 Results and Discussion Effect of temperature and time on PP recovery 0.136 0.145 0.155 0.164 0.173 Optimum - 0.173 g/g Infusion - 0.108 g/g 45:1 11.3 11.6 11.0 10.6 10.3 Optimum – 11.7 (mg/g) Infusion – 7.57 (mg/g) 45:1 Effect of temperature and time on L-Theanine Recovery Effect of temperature and WTR on ESY 0.263 0.271 0.255 0.286 0.278 50 min Optimum - 0.288 g/g Infusion – 0.226 g/g Effect of temperature and WTR on PP recovery 50 min Optimum - 0.173 g/g Infusion – 0.108g/g 11.3 10.2 10.6 10.9 11.6 Effect of Temperature and WTR on L-Theanine recovery Optimum – 11.7 mg/g Infusion – 7.57 mg/g 50 min Effect of time on tea quality parameters Effect of temperature on tea quality parameters Acknowledgement Optimizing yield and quality of green tea extract Samriddh Mudgal a,c, C.S. Murugesh a, L. Jaganmohan Rao b, B. Manohar a, R. Subramanian a a Department of Food Engineering b Department of Plantation Products, Spices and Flavour Technology Central Food Technological Research Institute (CSIR), Mysore 570 020, India c Department of Biotechnology, National Institute of Technology, Warangal 506 004, India Email: subbu@cftri.res.in  The extraction conditions were optimized with equal focus on polyphenols recovery and l-theanine recovery  The conditions standardized also co-extracted other tea components responsible for tea cream formation which could be addressed by an effective clarification process  Chemical quality parameters PES and TES were introduced for assessing the green tea extracts which could be used as benchmark quality parameters in the user industry  Box-Behnken Design explained the extraction phenomena and the model obtained provided close fit to the experimental results  The work demonstrated an optimization approach for obtaining the extract with greater solids yield rich in polyphenols and l-theanine having significant practical applications Samriddh Mudgal is thankful to Director, CFTRI for providing the opportunity and Chandini S. Kumar for valuable suggestions. Table 1: Tea solids, polyphenols and l-theanine recovery under specific and common optimized extraction conditions Table 2: Comparison of infusion and extract* quality ESY Maximum ESY of 28.8% was achieved at 44 min of extraction at 90  C which is 27.4% higher than the recovery obtained under normal brewing conditions (100:1 WTR; 75  C and 5 min). PP Recovery Maximum PP recovery recorded was 0.173 g/g for 50 min of extraction which was 60.2% higher than normal brew. L-Theanine Recovery L-theanine recovery increased up to 44 min of extraction and maximum recovery achieved was 54.5% higher than the normal brew. Effect of temperature and time on ESY 0.287 0.279 0.283 0.276 0.269 0.272 Optimum - 0.288 g/g Infusion - 0.226 g/g 45:1 * Obtained under optimized conditions *Common optimized conditions - 45:1; 50 min; 90ºC