This work presents the application of supercritical fluid extraction (SFE), an environmentally friendly methodology, to obtain broccoli leaves extracts with a high antioxidant activity. The following processing variables: pressure, temperature, percentage of ethanol and dynamic extraction time were optimised by means of a central composite design, combined with response surface methodology. The optimised conditions were applied to the extraction of broccoli leaves from different cultivars (Naxos, Nubia, Marathon, Parthenon and Viola). The optimal values of the extraction variables were 150 bars, 35 °C, 20 % ethanol and 10 min of dynamic extraction time. Percentage of ethanol and the combined effect of pressure and time were the factors that affected the extraction the most. The results obtained from different cultivars showed that the Naxos variety provided the extracts with the highest antioxidant activity and total phenolic content; moreover, DPPH (EC 50) values were higher than those previously reported for water extracts. The extracts were recovered in a small quantity of ethanol that could be easily eliminated, obtaining a residue free of contaminants.
SFE Broccoli leaves Antioxidant activity Total phenolic content DPPH ABTS
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The authors wish to thank the Junta de Castilla y León for financial support (GIR 127) and Dra. Cristina García Viguera (CEBAS-CSIC, Murcia) for the samples supplied. M.T. Martín would like to thank the Spanish Ministry of Science and Innovation for her “Ramón y Cajal” contract.
Compliance with Ethical Standards
This study was financially supported by Junta de Castilla y León (GIR 127).
Conflict of Interest
Esther Arnáiz declares that she has no conflict of interest. José Bernal declares that he has no conflict of interest. María Teresa Martín declares that she has no conflict of interest. Juan Carlos Diego declares that he has no conflict of interest. José Luis Bernal declares that he has no conflict of interest. Laura Toribio declares that she has no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
Informed consent is not applicable for this study.
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