Optimizing the extraction parameters of epigallocatechin gallate using conventional hot water and ultrasound assisted methods from green tea

[Display omitted] •Extraction parameters were optimized to maximize the epigallocatechin gallate content.•Epigallocatechin gallate content in hot water extraction was 3.86g/100g at optimum.•Ultrasound extraction with ethanol increased epigallocatechin gallate content by 100%.•Hot water extraction can easily be adapted to a pilot scale production. Epigallocatechin gallate (EGCG) is the main polyphenol present in green tea and is also known to possess various beneficial health effects. Extractions of EGCG, epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC) from green tea were investigated by both conventional hot water extraction and ultrasound assisted extraction (UAE) with water and ethanol. Response Surface Methodology was used in order to optimize the extraction conditions for obtaining maximum amount of EGCG in the extracts. Pilot scale conventional hot water extraction and UAE with water in continuous flow mode were also conducted for industrial use. UAE with ethanol was significantly (p