Value added utilization of agricultural and food industry by-products for the recovery of bioactive compounds has been widely recognized as an important area of research due to economic and environmental considerations. Main objective of this research project is to develop a sustainable processing methodology using pressurized low polarity water (PLPW) extraction for the recovery of bioactive extracts from black tea by-products focusing on tea polyphenols and tea saponins, bioactive compounds of great commercial significance. Multiple analytical and biological methods will be adapted for the analysis of the extracts to determine their polyphenol and saponin contents and their bioactivity (antioxidant and antibacterial activity). PLPW extraction conditions (temperature, time, sample pretreatment) will be optimized with respect to the bioactivity of the extracts and extract yields. Fractional extraction (at constant temperature and with a temperature gradient of 100-250˚C) will be carried out to investigate the selective recovery of bioactive components to obtain a spectrum of unique fractions with different compositions and activities. The use of elevated temperatures during PLPW extraction enables the investigation of the dual role of PLPW as a reaction medium and an extraction/fractionation solvent and its potential for the development of novel bioactive products. Mass transfer during PLPW extraction of tea polyphenols and saponins will be investigated to determine the mechanism that controls the extraction rate providing direction for further studies on the scale-up of the extraction process for industrial scale processing. Fractional PLPW extraction of polyphenols and saponins will be carried out at different solvent flow rates to investigate the mass tranfer during PLPW extraction. Two mathematical models will be used to describe PLPW extraction behavior: 1) a thermodynamic model (based on partition coefficient) and 2) the two-site kinetic (desorption) model