{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T07:29:47Z","timestamp":1782372587291,"version":"3.54.5"},"reference-count":37,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,3,25]],"date-time":"2018-03-25T00:00:00Z","timestamp":1521936000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Normally the olive oil quality is assessed by chemical analysis according to international standards. These norms define chemical and organoleptic markers, and depending on the markers, the olive oil can be labelled as lampante, virgin, or extra virgin olive oil (EVOO), the last being an indicator of top quality. The polyphenol content is related to EVOO organoleptic features, and different scientific works have studied the positive influence that these compounds have on human health. The works carried out in this paper are focused on studying relations between the polyphenol content in olive oil samples and its spectral response in the near infrared spectra. In this context, several acquisition parameters have been assessed to optimize the measurement process within the virgin olive oil production process. The best regression model reached a mean error value of 156.14 mg\/kg in leave one out cross validation, and the higher regression coefficient was 0.81 through holdout validation.<\/jats:p>","DOI":"10.3390\/s18040975","type":"journal-article","created":{"date-parts":[[2018,3,26]],"date-time":"2018-03-26T03:43:29Z","timestamp":1522035809000},"page":"975","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Non-Invasive Methodology to Estimate Polyphenol Content in Extra Virgin Olive Oil Based on Stepwise Multilinear Regression"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4150-5967","authenticated-orcid":false,"given":"Diego","family":"Mart\u00ednez Gila","sequence":"first","affiliation":[{"name":"Robotics, Automation and Computer Vision Group, University of Jaen, Campus Las Lagunillas s\/n, ES-23071 Jaen, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pablo","family":"Cano Marchal","sequence":"additional","affiliation":[{"name":"Robotics, Automation and Computer Vision Group, University of Jaen, Campus Las Lagunillas s\/n, ES-23071 Jaen, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan","family":"G\u00f3mez Ortega","sequence":"additional","affiliation":[{"name":"Robotics, Automation and Computer Vision Group, University of Jaen, Campus Las Lagunillas s\/n, ES-23071 Jaen, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Javier","family":"G\u00e1mez Garc\u00eda","sequence":"additional","affiliation":[{"name":"Robotics, Automation and Computer Vision Group, University of Jaen, Campus Las Lagunillas s\/n, ES-23071 Jaen, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,3,25]]},"reference":[{"key":"ref_1","unstructured":"International Olive Council (2014, January 24\u201328). Mercado Ole\u00edcola\u2014Newsletter N 88. Proceedings of the 102a Reuni\u00f3n del Consejo de Miembros, Madrid, Spain."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1016\/j.numecd.2009.12.007","article-title":"Olive oil and health: Summary of the II international conference on olive oil and health consensus report, Ja\u00e9n and C\u00f3rdoba (Spain) 2008","volume":"20","author":"Ros","year":"2010","journal-title":"Nutr. Metab. Cardiovasc. Dis."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1016\/j.riai.2011.06.013","article-title":"Situaci\u00f3n actual y perspectivas futuras del control del proceso de elaboraci\u00f3n del aceite de oliva virgen","volume":"8","author":"Marchal","year":"2011","journal-title":"Rev. Iberoam. Autom. Inf. Ind."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1002\/1438-9312(200210)104:9\/10<587::AID-EJLT587>3.0.CO;2-M","article-title":"Influence of olive processing on virgin olive oil quality","volume":"104","author":"Sestili","year":"2002","journal-title":"Eur. J. Lipid Sci. Technol."},{"key":"ref_5","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_6","unstructured":"Food and Drug Administration (2004). Guidance for Industry PAT\u2014A Framework for Innovative Pharmaceutical Development, Manufacturing, and Quality Assurance."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/j.tifs.2015.02.010","article-title":"The current status of process analytical technologies in the dairy industry","volume":"43","author":"Munir","year":"2015","journal-title":"Trends Food Sci. Technol."},{"key":"ref_8","unstructured":"Skibsted, E., and Engelsen, S.B. (2010). Encyclopedia of Spectroscopy and Spectrometry, Elsevier."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.tifs.2012.04.007","article-title":"Process Analytical Technology in the food industry","volume":"31","author":"Lyndgaard","year":"2013","journal-title":"Trends Food Sci. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4644","DOI":"10.1002\/jsfa.7733","article-title":"Novel Technologies for Monitoring the In-Line Quality of Virgin Olive Oil during Manufacturing and Storage","volume":"96","author":"Gila","year":"2016","journal-title":"J. Sci. Food Agric."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Gila, D.M., Puerto, D.A., Garc\u00eda, J.G., and Ortega, J.G. (2015, January 17\u201319). Automatic classification of olives for oil production using computer vision. Proceedings of the 2015 IEEE International Conference on Industrial Technology (ICIT), Seville, Spain.","DOI":"10.1109\/ICIT.2015.7125334"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1016\/j.jfoodeng.2013.05.032","article-title":"Expert system based on computer vision to estimate the content of impurities in olive oil samples","volume":"119","author":"Marchal","year":"2013","journal-title":"J. Food Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"15738","DOI":"10.3390\/s150715738","article-title":"Sorting Olive Batches for the Milling Process Using Image Processing","volume":"15","author":"Puerto","year":"2015","journal-title":"Sensors"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Gila, D.M., Marchal, P.C., Garcia, J.G., and Ortega, J.G. (2013, January 13\u201316). Control System of the Malaxing State for the Olive Paste Based on Computer Vision and Fuzzy Logic. Proceedings of the 2013 IEEE International Conference on Systems, Man, and Cybernetics, Manchester, UK.","DOI":"10.1109\/SMC.2013.335"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Morene, O.C., Gila, D.M., Puerto, D.A., Garc\u00eda, J.G., and Ortega, J.G. (2015, January 16\u201318). Automatic determination of peroxides and acidity of olive oil using machine vision in olive fruits before milling process. Proceedings of the 2015 IEEE International Conference on Imaging Systems and Techniques (IST), Macau, China.","DOI":"10.1109\/IST.2015.7294543"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1080\/10408390802606790","article-title":"The Use of Near-Infrared Spectrometry in the Olive Oil Industry","volume":"50","author":"Armenta","year":"2010","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1255\/jnirs.1106","article-title":"Review: Near infrared spectroscopy for analysing olive oils","volume":"22","author":"Casale","year":"2014","journal-title":"J. Near Infrared Spectrosc."},{"key":"ref_18","unstructured":"Bokobza, L. (2002). Near-Infrared Spectroscopy, Wiley-VCH Verlag GmbH."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"823","DOI":"10.1007\/s11746-004-0986-4","article-title":"Rapid evaluation of olive oil quality by NIR reflectance spectroscopy","volume":"81","author":"Mailer","year":"2004","journal-title":"J. Am. Oil Chem. Soc."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1255\/jnirs.597","article-title":"Comparison of Fourier transform near infrared spectroscopy partial least square regression models for South African extra virgin olive oil using spectra collected on two spectrophotometers at different resolutions and path lengths","volume":"14","author":"Manley","year":"2006","journal-title":"J. Near Infrared Spectrosc."},{"key":"ref_21","first-page":"250","article-title":"Evaluation of minor components, sensory characteristics and quality of virgin olive oil by Near Infrared (NIR) spectroscopy","volume":"50","author":"Fregapane","year":"2012","journal-title":"Food Res. Int."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1255\/jnirs.1155","article-title":"Near infrared spectroscopy and artificial neural network to characterise olive fruit and oil online for process optimisation","volume":"23","author":"Allouche","year":"2015","journal-title":"J. Near Infrared Spectrosc."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"861","DOI":"10.1002\/jsfa.6733","article-title":"Sample presentation, sources of error and future perspectives on the application of vibrational spectroscopy in the wine industry","volume":"95","author":"Cozzolino","year":"2015","journal-title":"J. Sci. Food Agric."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1317","DOI":"10.1007\/s11746-011-1787-y","article-title":"Influence of Turbidity Grade on Color and Appearance of Virgin Olive Oil","volume":"88","author":"Gordillo","year":"2011","journal-title":"J. Am. Oil Chem. Soc."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/j.jfoodeng.2012.03.034","article-title":"On-line analysis of intact olive fruits by vis-NIR spectroscopy: Optimisation of the acquisition parameters","volume":"112","author":"Baeten","year":"2012","journal-title":"J. Food Eng."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1461","DOI":"10.1111\/ijfs.12790","article-title":"Optical path length and wavelength selection using Vis\/NIR spectroscopy for olive oil\u2019s free acidity determination","volume":"50","year":"2015","journal-title":"Int. J. Food Sci. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"9017","DOI":"10.1021\/jf3026666","article-title":"Analysis of total contents of hydroxytyrosol and tyrosol in olive oils","volume":"60","author":"Romero","year":"2012","journal-title":"J. Agric. Food Chem."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Stuart, B.H. (2004). Infrared Spectroscopy: Fundamentals and Applications, John Wiley & Sons.","DOI":"10.1002\/0470011149"},{"key":"ref_29","unstructured":"Workman, J. (2008). Handbook of Near-Infrared Analysis, CRC Press."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"772","DOI":"10.1366\/0003702894202201","article-title":"Standard Normal Variate Transformation and De-trending of Near-Infrared Diffuse Reflectance Spectra","volume":"43","author":"Barnes","year":"1989","journal-title":"Appl. Spectrosc."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1366\/0003702854248656","article-title":"Correction for Near-Infrared Reflectance Spectra of Meat","volume":"39","author":"Geladi","year":"1985","journal-title":"Appl. Spectrosc."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.1021\/ac60214a047","article-title":"Smoothing and Differentiation of Data by Simplified Least Squares Procedures","volume":"36","author":"Savitzky","year":"1964","journal-title":"Anal. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Workman, J., and Weyer, L. (2012). Practical Guide and Spectral Atlas for Interpretive Near-Infrared Spectroscopy, CRC Press. [2nd ed.].","DOI":"10.1201\/b11894"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.knosys.2014.03.015","article-title":"Binary PSO with mutation operator for feature selection using decision tree applied to spam detection","volume":"64","author":"Zhang","year":"2014","journal-title":"Knowl.-Based Syst."},{"key":"ref_35","unstructured":"Howard, M. (2008). Handbook of Near-Infrared Analysis, CRC Press."},{"key":"ref_36","unstructured":"MathWorks (2017). Statistics and Machine Learning Toolbox: User\u2019s Guide, The MathWorks, Inc."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1016\/j.lwt.2004.10.007","article-title":"Multivariate determination of free fatty acids and moisture in fish oils by partial least-squares regression and near-infrared spectroscopy","volume":"38","author":"Cozzolino","year":"2005","journal-title":"LWT Food Sci. Technol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/4\/975\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:58:28Z","timestamp":1760194708000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/4\/975"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,3,25]]},"references-count":37,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2018,4]]}},"alternative-id":["s18040975"],"URL":"https:\/\/doi.org\/10.3390\/s18040975","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,3,25]]}}}