{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T12:13:02Z","timestamp":1773835982490,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,19]],"date-time":"2022-09-19T00:00:00Z","timestamp":1663545600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003093","name":"Ministry of Higher Education Malaysia through the Fundamental Research Grant Scheme","doi-asserted-by":"publisher","award":["FRGS\/1\/2020\/TK0\/UKM\/02\/7"],"award-info":[{"award-number":["FRGS\/1\/2020\/TK0\/UKM\/02\/7"]}],"id":[{"id":"10.13039\/501100003093","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003093","name":"Ministry of Higher Education Malaysia through the Fundamental Research Grant Scheme","doi-asserted-by":"publisher","award":["UKM-YSD-2021-008"],"award-info":[{"award-number":["UKM-YSD-2021-008"]}],"id":[{"id":"10.13039\/501100003093","id-type":"DOI","asserted-by":"publisher"}]},{"name":"UKM-YSD Sustainability Chair Research Grant","award":["FRGS\/1\/2020\/TK0\/UKM\/02\/7"],"award-info":[{"award-number":["FRGS\/1\/2020\/TK0\/UKM\/02\/7"]}]},{"name":"UKM-YSD Sustainability Chair Research Grant","award":["UKM-YSD-2021-008"],"award-info":[{"award-number":["UKM-YSD-2021-008"]}]},{"name":"Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM)","award":["FRGS\/1\/2020\/TK0\/UKM\/02\/7"],"award-info":[{"award-number":["FRGS\/1\/2020\/TK0\/UKM\/02\/7"]}]},{"name":"Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM)","award":["UKM-YSD-2021-008"],"award-info":[{"award-number":["UKM-YSD-2021-008"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The degree of maturity of oil palm fresh fruit bunches (FFB) at the time of harvest heavily affects oil production, which is expressed in the oil extraction rate (OER). Oil palm harvests must be harvested at their optimum maturity to maximize oil yield if a rapid, non-intrusive, and accurate method is available to determine their level of maturity. This study demonstrates the potential of implementing Raman spectroscopy for determining the maturity of oil palm fruitlets. A ripeness classification algorithm has been developed utilizing machine learning by classifying the components of organic compounds such as \u03b2-carotene, amino acid, etc. as parameters to distinguish the ripeness of fruits. In this study, 47 oil palm fruitlets spectra from three different ripeness levels\u2014under ripe, ripe, and over ripe\u2014were examined. To classify the oil palm fruitlets into three maturity categories, the extracted features were put to the test using 31 machine learning models. It was discovered that the Medium, Weighted KNN, and Trilayered Neural Network classifier has a maximum overall accuracy of 90.9% by using four significant features extracted from the peaks as the predictors. To conclude, the Raman spectroscopy method may offer a precise and efficient means to evaluate the maturity level of oil palm fruitlets.<\/jats:p>","DOI":"10.3390\/s22187091","type":"journal-article","created":{"date-parts":[[2022,9,20]],"date-time":"2022-09-20T04:28:55Z","timestamp":1663648135000},"page":"7091","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Correlation Study between the Organic Compounds and Ripening Stages of Oil Palm Fruitlets Based on the Raman Spectra"],"prefix":"10.3390","volume":"22","author":[{"given":"Muhammad Haziq Imran Md","family":"Azmi","sequence":"first","affiliation":[{"name":"Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fazida Hanim","family":"Hashim","sequence":"additional","affiliation":[{"name":"Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia"},{"name":"Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aqilah Baseri","family":"Huddin","sequence":"additional","affiliation":[{"name":"Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8400-8090","authenticated-orcid":false,"given":"Mohd Shaiful","family":"Sajab","sequence":"additional","affiliation":[{"name":"Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia"},{"name":"Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Mat Sharif, Z.B., Mohd Taib, N.B., Bin Yusof, M.S., Bin Rahim, M.Z., Bin Mohd Tobi, A.L., and Bin Othman, M.S. 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