Isolation of gallic acid, caffeine and flavonols from black tea by on-line coupling of pressurized liquid extraction with an adsorbent for the production of functional bakery products

The objective of this work was to evaluate the on-line coupling of pressurized liquid extraction with an adsorbent for the simultaneous extraction and separation of flavonols of black tea, producing a concentrated extract that could be used as ingredient for the production of functional bakery products. After the evaluation of different adsorbents, extraction temperatures and solvents, a two-stage process was developed which was capable of producing three extracts: one with high concentration of gallic acid (78.97 +/- 5.49 mg/L), another one with high concentration of caffeine (109.72 +/- 3.15 mg/L) and a highly concentrated flavonol extract (322.0 +/- 4.50 mg/L). The developed method uses greener solvents (water and ethanol) and is capable of producing higher flavonol (similar to 50%) yields than conventional methods. The introduction of the flavonol extract in the dough can be used for the development of functional bakery since compounds were stable under processing conditions.