Optimization of ultrasound-assisted extraction of polyphenols from globe artichoke (Cynara scolymus L.) bracts residues using response surface methodology.

Background: The globe artichoke (Cynara scolymus L.) is a rich source of phenolic compounds which may be extracted by ultrasound technology and used as a medicinal alternative. The objective of this work was to determine the radiation amplitude (%), ethanol concentration (%), and time extraction (min) required to guarantee an elevated content of polyphenol compounds.

Methods: The optimal extraction conditions were assessed through the Box-Wilson design and by applying Composite Face Centered (CCFC) and total phenolic compounds (TPC) as the response variables.

Results: A quadratic model was adequate, with R2 = 0.993. The optimal conditions were a radiation amplitude of 97%, an ethanol concentration of 53%, and an extraction time of 9.7 min. The optimized extract of artichoke bracts (Cynara scolymus L.) showed a TPC of 25.13 (±0.030) mg GAE/g, an antioxidant activity DPPH of 39.79 (±0.014) mmol Trolox equivalents (TE), and an antioxidant capacity TEAC of 33.98 (±0.03) mmol Trolox equivalents.

Conclusions: The results showed values closely related to the expected values, indicating that the models were well-developed.