{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T10:58:42Z","timestamp":1787741922450,"version":"build-2784847793"},"reference-count":51,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,4,12]],"date-time":"2025-04-12T00:00:00Z","timestamp":1744416000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Next Generation EU funds"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Foods"],"abstract":"<jats:p>This study investigated the impact of acidification on olive paste to enhance the extraction of olive oil enriched in bioactive phenolic compounds, aiming to develop a novel functional food. Recognizing that acidic pH promotes the activity of \u03b2-glucosidase responsible for oleuropein and ligstroside hydrolysis, food-grade organic acids\u2014citric, ascorbic, and acetic acid\u2014were added prior to malaxation to improve the bioactive compound content in the resulting oils. A randomized experimental design was employed, using three different doses of each acid (1, 2, and 4%) with three replicates per dose, alongside control trials without acid addition. Acidification did not affect olive oil extraction efficiency or alter quality parameters for extra virgin olive oils. Treatment with 1% ascorbic acid significantly increased phenolic compound content by 37% compared to controls. Secoiridoids comprised 79.4% of the total phenolic content, with oleacein as the predominant compound (237.58 \u00b1 9.18 mg\/kg), representing over 50% of the total. This increased oleacein concentration led to up to a 67% enhancement in antioxidant capacity (428.63 \u00b1 31.57 mg Trolox\/kg) compared to controls. The antioxidant capacities of 3,4-DHPEA, 3,4-DHPEA-EDA, and 3,4-DHPEA-EA were determined to be 12.05, 5.80, and 4.91 \u00b5mol TE\/mg, respectively. Furthermore, the 1% ascorbic acid treatment enhanced volatile compounds associated with the lipoxygenase (LOX) pathway while reducing ethanol levels.<\/jats:p>","DOI":"10.3390\/foods14081336","type":"journal-article","created":{"date-parts":[[2025,4,14]],"date-time":"2025-04-14T03:39:16Z","timestamp":1744601956000},"page":"1336","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Increasing the Bioactive Compound Content of Olive Oil by Acidification of Olive Paste"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-0840-9973","authenticated-orcid":false,"given":"Ra\u00fal","family":"Peralta","sequence":"first","affiliation":[{"name":"Chemical, Environmental and Materials Engineering Department, University of Ja\u00e9n, Paraje Las Lagunillas, 23071 Ja\u00e9n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3803-1876","authenticated-orcid":false,"given":"Alfonso M.","family":"Vidal","sequence":"additional","affiliation":[{"name":"Chemical, Environmental and Materials Engineering Department, University of Ja\u00e9n, Paraje Las Lagunillas, 23071 Ja\u00e9n, Spain"},{"name":"Institute of Biorefineries Research (I3B), University of Ja\u00e9n, Campus Las Lagunillas, 23071 Ja\u00e9n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9570-6297","authenticated-orcid":false,"given":"Francisco","family":"Esp\u00ednola","sequence":"additional","affiliation":[{"name":"Chemical, Environmental and Materials Engineering Department, University of Ja\u00e9n, Paraje Las Lagunillas, 23071 Ja\u00e9n, Spain"},{"name":"Institute of Biorefineries Research (I3B), University of Ja\u00e9n, Campus Las Lagunillas, 23071 Ja\u00e9n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6944-8178","authenticated-orcid":false,"given":"Mar\u00eda Teresa","family":"Oca\u00f1a","sequence":"additional","affiliation":[{"name":"Science Didactics Department, University of Ja\u00e9n, Paraje Las Lagunillas, 23071 Ja\u00e9n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9820-396X","authenticated-orcid":false,"given":"Manuel","family":"Moya","sequence":"additional","affiliation":[{"name":"Chemical, Environmental and Materials Engineering Department, University of Ja\u00e9n, Paraje Las Lagunillas, 23071 Ja\u00e9n, Spain"},{"name":"Institute of Biorefineries Research (I3B), University of Ja\u00e9n, Campus Las Lagunillas, 23071 Ja\u00e9n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"101","DOI":"10.18335\/region.v5i1.219","article-title":"The Mediterranean Diet and the Increasing Demand of the Olive Oil Sector: Shifts and Environmental Consequences","volume":"5","author":"Neves","year":"2018","journal-title":"Region"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"370","DOI":"10.1016\/j.lwt.2017.05.069","article-title":"Filtered vs. naturally sedimented and decanted virgin olive oil during storage: Effect on quality and composition","volume":"84","author":"Mofardin","year":"2017","journal-title":"LWT"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3390\/antiox3010001","article-title":"Biological Activities of Phenolic Compounds of Extra Virgin Olive Oil","volume":"3","author":"Servili","year":"2014","journal-title":"Antioxidants"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.fct.2012.12.049","article-title":"Anti-apoptotic activity of hydroxytyrosol and hydroxytyrosyl laurate","volume":"55","author":"Burattini","year":"2013","journal-title":"Food Chem. Toxicol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Parkinson, L., and Cicerale, S. (2016). The Health Benefiting Mechanisms of Virgin Olive Oil Phenolic Compounds. Molecules, 21.","DOI":"10.3390\/molecules21121734"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Souza, P.A., Marcadenti, A., and Portal, V.L. (2017). Effects of Olive Oil Phenolic Compounds on Inflammation in the Prevention and Treatment of Coronary Artery Disease. Nutrients, 9.","DOI":"10.3390\/nu9101087"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/j.bpc.2017.09.002","article-title":"Bioactive compounds from extra virgin olive oils: Correlation between phenolic content and oxidative stress cell protection","volume":"230","author":"Presti","year":"2017","journal-title":"Biophys. Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1016\/j.tifs.2019.03.008","article-title":"Health benefits of olive oil and its components: Impacts on gut microbiota antioxidant activities, and prevention of noncommunicable diseases","volume":"88","author":"Gavahian","year":"2019","journal-title":"Trends Food Sci. Technol."},{"key":"ref_9","first-page":"1","article-title":"Positive Health Effects of Olive Oil","volume":"13","author":"Drlje","year":"2021","journal-title":"Eur. J. Nutr. Food Saf."},{"key":"ref_10","unstructured":"European Commission (2025, February 10). Commission Regulation No 432\/2012, Establishing a List of Permitted Health Claims Made on Foods, Other Than Those Referring to the Reduction of Disease Risk and to Children\u2019s Development and Health 2012. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/PDF\/?uri=CELEX:32012R0432."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.lwt.2017.12.003","article-title":"Assessment of phenolic compounds in virgin olive oil by response surface methodology with particular focus on flavonoids and lignans","volume":"90","author":"Moya","year":"2018","journal-title":"LWT"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1007\/BF02490424","article-title":"HPLC and HRGC analyses of polyphenols and secoiridoid in olive oil","volume":"53","author":"Romani","year":"2001","journal-title":"Chromatographia"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Bendini, A., Cerretani, L., Carrasco-Pancorbo, A., G\u00f3mez-Caravaca, A.M., Segura-Carretero, A., Fern\u00e1ndez-Guti\u00e9rrez, A., and Lercker, G. (2007). Phenolic Molecules in Virgin Olive Oils: A Survey of Their Sensory Properties, Health Effects, Antioxidant Activity and Analytical Methods. An Overview of the Last Decade Alessandra. Molecules, 12.","DOI":"10.3390\/12081679"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1016\/j.talanta.2007.04.045","article-title":"Study of the phenolic composition of spanish and italian monocultivar extra virgin olive oils: Distribution of lignans, secoiridoidic, simple phenols and flavonoids","volume":"73","author":"Innocenti","year":"2007","journal-title":"Talanta"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"6609","DOI":"10.1021\/jf070599n","article-title":"Irrigation Effects on Quality, Phenolic Composition, and Selected Volatiles of Virgin Olive Oils Cv. Leccino","volume":"55","author":"Servili","year":"2007","journal-title":"J. Agric. Food Chem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"9569","DOI":"10.1021\/jf5027982","article-title":"Endogenous enzymes involved in the transformation of oleuropein in Spanish table olive varieties","volume":"62","author":"Medina","year":"2014","journal-title":"J. Agric. Food Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1016\/j.foodchem.2014.09.009","article-title":"Modulating oxidoreductase activity modifies the phenolic content of virgin olive oil","volume":"171","author":"Sanz","year":"2015","journal-title":"Food Chem."},{"key":"ref_18","unstructured":"Clodoveo, M., Camposeo, S., Amirante, R., Dugo, G., Cicero, N., and Boskou, D. (2015). Olive and Olive Oil Bioactive Constituents, AOCS Press."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.jfca.2017.04.016","article-title":"Effect of Tunisian olive ripeness on endogenous enzymes and virgin olive oil phenolic composition","volume":"62","author":"Kotti","year":"2017","journal-title":"J. Food Compos. Anal."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1007\/s00217-005-0160-5","article-title":"Changes in quality and phenolic compounds of virgin olive oils during objectively de-scribed fruit maturation","volume":"223","author":"Yousfi","year":"2006","journal-title":"Eur. Food Res. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"3587","DOI":"10.1021\/jf803505w","article-title":"Effect of Malaxation Conditions on Phenol and Volatile Profiles in Olive Paste and the Corresponding Virgin Olive Oils (Olea europaea L. Cv. Cornicabra)","volume":"57","author":"Salvador","year":"2009","journal-title":"J. Agric. Food Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"5409","DOI":"10.1002\/jsfa.11189","article-title":"Study of the olive \u03b2-glucosidase gene family putatively involved in the synthesis of phenolic compounds of virgin olive oil","volume":"101","author":"Sanz","year":"2021","journal-title":"J. Sci. Food Agric."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1016\/j.jnutbio.2017.12.006","article-title":"Oleocanthal-rich extra-virgin olive oil enhances donepezil effect by reducing amyloid-\u03b2 load and related toxicity in a mouse model of Alzheimer\u2019s disease","volume":"55","author":"Batarseh","year":"2018","journal-title":"J. Nutr. Biochem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.jff.2017.06.046","article-title":"Oleocanthal-rich extra virgin olive oil demonstrates acute anti-platelet effects in healthy men in a randomized trial","volume":"36","author":"Agrawal","year":"2017","journal-title":"J. Funct. Foods"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"406","DOI":"10.1016\/j.drudis.2014.10.017","article-title":"New drugs from ancient natural foods. Oleocanthal, the natural occurring spicy compound of olive oil: A brief history","volume":"20","author":"Scotece","year":"2015","journal-title":"Drug Discov. Today"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1255","DOI":"10.1016\/j.phymed.2015.10.005","article-title":"Oleacein enhances anti-inflammatory activity of human macrophages by increasing CD163 receptor expression","volume":"22","author":"Filipek","year":"2015","journal-title":"Phytomedicine"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1016\/j.phymed.2017.06.004","article-title":"Oleacein may inhibit destabilization of carotid plaques from hypertensive patients. Impact on high mobility group protein-1","volume":"32","author":"Filipek","year":"2017","journal-title":"Phytomedicine"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"4332","DOI":"10.1002\/ejoc.201300324","article-title":"A Concise and Efficient Total Synthesis of Oleocanthal","volume":"2013","author":"Valli","year":"2013","journal-title":"Eur. J. Org. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1016\/j.foodchem.2014.08.079","article-title":"Preparative isolation of oleocanthal, tyrosol, and hydroxytyrosol from olive oil by HPCCC","volume":"170","author":"Adhami","year":"2015","journal-title":"Food Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1016\/j.chroma.2017.02.046","article-title":"An integrated process for the recovery of high added-value compounds from olive oil using solid support free liquid-liquid extraction and chromatography techniques","volume":"1491","author":"Angelis","year":"2017","journal-title":"J. Chromatogr. A"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1459","DOI":"10.1007\/s00217-020-03503-1","article-title":"Elaboration of extra-virgin olive oils rich in oleocanthal and oleacein: Pilot plant\u2019s proposal","volume":"246","author":"Vidal","year":"2020","journal-title":"Eur. Food Res. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Millao, S., Quilaqueo, M., Contardo, I., and Rubilar, M. (2025). Enhancing the Oxidative Stability of Beeswax\u2013Canola Oleogels: Effects of Ascorbic Acid and Alpha-Tocopherol on Their Physical and Chemical Properties. Gels, 11.","DOI":"10.3390\/gels11010043"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3712","DOI":"10.1002\/fsn3.2332","article-title":"Improving the oxidative stability of virgin olive oil using microformulated vitamin-C","volume":"9","author":"Osanloo","year":"2021","journal-title":"Food Sci. Nutr."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Cuomo, F., Cinelli, G., Chirascu, C., Marconi, E., and Lopez, F. (2020). Antioxidant Effect of Vitamins in Olive Oil Emulsion. Colloids Interfaces, 4.","DOI":"10.3390\/colloids4020023"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1085","DOI":"10.1080\/10942912.2016.1199037","article-title":"Effects of \u03b1-Tocopherol and Citric Acid on the Oxidative Stability of Alimentary Poultry Fats During Storage at Low Temperatures","volume":"20","author":"Flavia","year":"2017","journal-title":"Int. J. Food Prop."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1016\/j.foodchem.2009.02.077","article-title":"The effect of citric acid on the phenolic contents of olive oil","volume":"116","author":"Aliakbarian","year":"2009","journal-title":"Food Chem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"e250","DOI":"10.3989\/gya.1220172","article-title":"Modeling of volatile and phenolic compounds and optimization of the process conditions for obtaining balanced extra virgin olive oils","volume":"69","author":"Torres","year":"2018","journal-title":"Grasas Aceites"},{"key":"ref_38","unstructured":"European Commission (2025, February 10). Commission Regulation No 2568\/91, on the Characteristics of Olive Oil and Olive-Residue Oil and on the Relevant Methods of Analysis 1991. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/PDF\/?uri=CELEX:31991R2568."},{"key":"ref_39","unstructured":"International Olive Council (2025, February 10). Determination of Biophenols in Olive Oils by HPLC. COI\/T.20\/Doc No 29\/Rev 2 2022. Available online: https:\/\/www.internationaloliveoil.org\/wp-content\/uploads\/2022\/10\/COI-T20-Doc.-29-REV-1-2017-Eng.pdf."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Vidal, A.M., Moya, M., Alcal\u00e1, S., Romero, I., and Esp\u00ednola, F. (2022). Enrichment of Refined Olive Oils with Phenolic Extracts of Olive Leaf and Exhausted Olive Pomace. Antioxidants, 11.","DOI":"10.3390\/antiox11020204"},{"key":"ref_41","unstructured":"European Commission (2025, February 10). Regulation (EU) No 1308\/2013 of the European Parliament and of the Council of 17 December 2013 Establishing a Common Organisation of the Markets in Agricultural Products and Repealing Council Regulations (EEC) No 922\/72, (EEC) No 234\/79, (EC) No 1037\/2001 and (EC) No 1234\/2007 2013. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/PDF\/?uri=CELEX:02013R1308-20241108."},{"key":"ref_42","unstructured":"International Olive Council (2025, February 10). Sensory Analysis of Olive Oil. COI\/T.20\/Doc No 4\/Rev 1 2007. Available online: https:\/\/www.internationaloliveoil.org\/wp-content\/uploads\/2019\/11\/COI-T.20-Doc.-No-4-Rev1-2007-Eng.pdf."},{"key":"ref_43","unstructured":"Chabni, A., Ba\u00f1ares, C., V\u00e1zquez, L., and Torres, C.F. Combination of expeller and supercritical CO2 for the extraction of a phenolic-rich olive oil\u2014A preliminary chemical characterization, J. Ind. Eng. Chem., in press."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"100922","DOI":"10.1016\/j.focha.2025.100922","article-title":"Quantitative estimation of pharmacologically relevant phenolic compounds in olive oils harvested in Jabal Al Akhdar in Oman","volume":"6","author":"Suliman","year":"2025","journal-title":"Food Chem. Adv."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1016\/j.foodchem.2018.06.002","article-title":"Cultivar influence on variability in olive oil phenolic profiles determined through an extensive germplasm survey","volume":"266","author":"Miho","year":"2018","journal-title":"Food Chem."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"106128","DOI":"10.1016\/j.jfca.2024.106128","article-title":"Deciphering the influence of the cultivar on the phenolic content of virgin olive oil","volume":"129","author":"Miho","year":"2024","journal-title":"J. Food Compos. Anal."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"128291","DOI":"10.1016\/j.foodchem.2020.128291","article-title":"Olive oil varieties and ripening stages containing the antioxidants hydroxytyrosol and derivatives in compliance with EFSA health claim","volume":"342","year":"2021","journal-title":"Food Chem."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"133327","DOI":"10.1016\/j.foodchem.2022.133327","article-title":"Impact of fresh olive leaves addition during the extraction of Arbequina virgin olive oils on the phenolic and volatile profiles","volume":"393","author":"Marx","year":"2022","journal-title":"Food Chem."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"55","DOI":"10.5650\/jos.ess13114","article-title":"Oxidative stability, phenolic compounds and antioxidant potential of a virgin olive oil enriched with natural bioactive compounds","volume":"63","author":"Baltasar","year":"2014","journal-title":"J. Oleo Sci."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"661","DOI":"10.1002\/1438-9312(200210)104:9\/10<614::AID-EJLT614>3.0.CO;2-L","article-title":"Characterisation of monovarietal virgin olive oil","volume":"104","author":"Aparicio","year":"2002","journal-title":"Eur. J. Lipid Sci. Technol."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Peralta, R., Esp\u00ednola, F., Vidal, A.M., and Moya, M. (2024). Olive Oil (Royal Cultivar) from Mill Obtained by Short Time Malaxation and Early Ripening Stage. Foods, 13.","DOI":"10.3390\/foods13162588"}],"container-title":["Foods"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2304-8158\/14\/8\/1336\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:13:27Z","timestamp":1760030007000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2304-8158\/14\/8\/1336"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,12]]},"references-count":51,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2025,4]]}},"alternative-id":["foods14081336"],"URL":"https:\/\/doi.org\/10.3390\/foods14081336","relation":{},"ISSN":["2304-8158"],"issn-type":[{"value":"2304-8158","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,12]]}}}