Optimization of the Enzymatic Extraction of Naringenin from Pink Grapefruit Pulp (Citrus x paradisi Macfad.)

Naringenin is one of the main phenolic compounds found in grapefruit (Citrus x paradisi Macfad.). This compound is known for its therapeutical properties as an antioxidant, antidiabetic, antihyperlipidemic and antineoplastic agent. In order to enable the development of drugs based on this compound, an appropriate extraction method needs to be developed. For this study, enzymatic extraction was chosen, as it is a cheap and green extraction method. Optimal extraction conditions (pH, temperature, agitation, solvent composition, sample-to-solvent ratio and enzyme-to-sample ratio) were determined through a Plackett-Burman and a Box-Behnken design, resulting in pH 6.0, 40 degrees C, 50 rpm, 20% EtOH, 0.2 g sample per 15 mL solvent and 1000 U/g. Once extraction conditions were determined, a single-factor experiment was performed under optimal conditions to determine extraction time, which resulted in 10 min per extraction. Finally, repeatability and intermediate precision were evaluated through naringenin quantification. Good values were obtained for both parameters (1.80% and 2.05%, respectively). Furthermore, extracts presented significant amount of naringenin (0.18 +/- 0.02 mg/g).