Olive pomace, an environmentally detrimental residue generated during olive oil extraction,
contains bioactive compounds in demand by the food industry. To valorize this waste product a
suitable yield for the extraction process is required. Heat-assisted extraction of bioactive compounds
from olive pomace was optimized by a circumscribed central composite design and response surface
methodology. Our previous studies indicated that irradiation could improve 2.4-fold the extractability
of the main phenolic compounds from olive pomace. The effect of extraction time, temperature and
solvent concentration on the yield of polyphenols from irradiated olive pomace at 5 kGy was tested.
Hydroxytyrosol-1- -glucoside, hydroxytyrosol, tyrosol and caffeic acid were quantified by High
Performance Liquid Chromatography to calculate the total polyphenol content. The optimal general
conditions by RSM modeling were extraction time of 120 min, temperature of 85 C, and 76% of
ethanol in water. Using these selected conditions, 19.04 1.50 mg/g dry weight, 148.88 8.73 mg/g
extract of total polyphenols were obtained, representing a yield of 13.7%, which was consistent with
the value predicted by the model. This work demonstrated the potential of residues from the olive
oil industry as a suitable alternative to obtain compounds that could be used as ingredients for the
food industry.
This work was funded by the Foundation for Science and Technology (FCT, Portugal)
for financial support through national funds FCT/MCTES to C2TN (UIDB/04349/2020), CIMO
(UIDB/00690/2020), J.M. (SFRH/BD/136506/2018); L.B. thank the national funding by FCT, P.I.,
through the institutional scientific employment program-contract; and the European Regional Development
Fund (ERDF) through the Regional Operational Program North 2020, within the scope of
Project OliveBIOextract (NORTE-01-0247-FEDER-049865). The GIP-USAL is funded by the Strategic
Research Programs for Units of Excellence (ref CLU-2018-04) and Consejería de Educación de la Junta
de Castilla y León (Project SA093P20).
