Recovery of oils and antioxidants from olive stones


The olive oil industry generates enormous amounts of olive stones each year, which have the potential to be used as a biofuel but have high oil content, which negatively impacts the combustion process. In addition, olive stones contain high-value antioxidants, and their exploitation can provide additional revenues for the biofuel industry. In this work, we report the effect of different extraction solvents on the extraction of antioxidants and their activity. In addition, in vitro gastrointestinal digestion was used to evaluate the content and antioxidant activity of the olive stone extracts after gastrointestinal digestion. The extracts obtained by aqueous ethanol solvent (50% vol) exhibited the highest antioxidant activity with the DPPH IC50 of 1.27 mg mL−1 and ferric reducing antioxidant power (FRAP) of 6.33 mg AAE g−1. After in vitro digestion composed of gastric and intestinal processes, the antioxidant activity of olive stones decreased: DPPH IC50 value increased three times (a higher value of IC50 indicates lower antioxidant activity) and FRAP decreased almost five times with respect to the values obtained for original extracts. Furthermore, both phenomenological and shrinking core models were used to fit experimental oil extraction kinetics data and showed good agreement. Thermodynamic analysis showed that the extraction process is endothermic and irreversible while spontaneous and thermodynamically favourable for all conditions except for oil extraction from olive stones of 3.10 mm particle size at 20 °C. The calculated value for temperature coefficient is in good agreement with the previously reported values for the oil extraction from similar biomass.

Publication DOI:
Divisions: College of Engineering & Physical Sciences > Energy and Bioproducts Research Institute (EBRI)
College of Engineering & Physical Sciences
College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
Additional Information: © 2022, The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license ( Funding: This work was supported by the Engineering and Physical Sciences Research Council – Impact Acceleration Account.
Uncontrolled Keywords: Olive stones,Antioxidants,Kinetics of oil extraction,Thermodynamics of oil extraction,Gastrointestinal digestion,Solvent extraction
Publication ISSN: 1873-2909
Last Modified: 29 May 2024 17:50
Date Deposited: 04 Nov 2022 17:11
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Related URLs: https://www.sci ... 961953422002859 (Publisher URL)
PURE Output Type: Article
Published Date: 2022-11
Published Online Date: 2022-10-21
Accepted Date: 2022-10-09
Authors: Osei, Joseph B.D.
Amiri, Amirpiran (ORCID Profile 0000-0001-7838-3249)
Wang, Jiawei (ORCID Profile 0000-0001-5690-9107)
Tavares, Marcia T.
Kiatkittipong, Worapon
Najdanovic-Visak, Vesna (ORCID Profile 0000-0002-1035-0982)



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