biostudies-literatureUnknown13Rajapaksha SSpent black tea (SBT) is a residue from tea beverage production and considered as a potential source of active polyphenols. This study aimed to develop a pilot-scale process on semi-continuous subcritical solvent extraction (SSE) of polyphenols from SBT by exploiting the lab-scale knowledge. Treatment of SBT with ethanol-water (50% w/w) as solvent at 125 °C and 0.3 MPa achieved a significantly higher yield of polyphenols (80.82 g gallic acid equivalents/kg black tea) with antioxidant activity (64.20 g gallic acid equivalents/kg black tea), compared to hot water extraction (HWE). SSE increased the soluble matter content in extracts than HWE. Based on the results of LC-MS, theaflavin-3,3'-digallate was the most abundant polyphenol from a total of 12 compounds to be extracted by SBT with 50% Food chemistry: X100200https://www.ebi.ac.uk/biostudies/studies/S-EPMC9039883biostudies-literaturePilot-scale extraction of polyphenols from spent black tea by semi-continuous subcritical solvent extraction.PMC9039883Shimizu NRajapaksha SfalsePilot-scale extraction of polyphenols from spent black tea by semi-continuous subcritical solvent extraction.Spent black tea (SBT) is a residue from tea beverage production and considered as a potential source of active polyphenols. This study aimed to develop a pilot-scale process on semi-continuous subcritical solvent extraction (SSE) of polyphenols from SBT by exploiting the lab-scale knowledge. Treatment of SBT with ethanol-water (50% w/w) as solvent at 125 °C and 0.3 MPa achieved a significantly higher yield of polyphenols (80.82 g gallic acid equivalents/kg black tea) with antioxidant activity (64.20 g gallic acid equivalents/kg black tea), compared to hot water extraction (HWE). SSE increased the soluble matter content in extracts than HWE. Based on the results of LC-MS, theaflavin-3,3'-digallate was the most abundant polyphenol from a total of 12 compounds to be extracted by SBT with 50% 2022-01-01T00:00:00Z2022 Mar2025-04-19T08:39:39.765Z2025-02-19T04:20:51.241ZS-EPMC90398833549899710.1016/j.fochx.2021.100200