{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T15:44:54Z","timestamp":1787067894139,"version":"build-2736575974"},"reference-count":41,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2012,5,10]],"date-time":"2012-05-10T00:00:00Z","timestamp":1336608000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In recent years, there have been a number of reported studies on the use of non-destructive techniques to evaluate and determine mango maturity and ripeness levels. However, most of these reported works were conducted using single-modality sensing systems, either using an electronic nose, acoustics or other non-destructive measurements. This paper presents the work on the classification of mangoes (Magnifera Indica cv. Harumanis) maturity and ripeness levels using fusion of the data of an electronic nose and an acoustic sensor. Three groups of samples each from two different harvesting times (week 7 and week 8) were evaluated by the e-nose and then followed by the acoustic sensor. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were able to discriminate the mango harvested at week 7 and week 8 based solely on the aroma and volatile gases released from the mangoes. However, when six different groups of different maturity and ripeness levels were combined in one classification analysis, both PCA and LDA were unable to discriminate the age difference of the Harumanis mangoes. Instead of six different groups, only four were observed using the LDA, while PCA showed only two distinct groups. By applying a low level data fusion technique on the e-nose and acoustic data, the classification for maturity and ripeness levels using LDA was improved. However, no significant improvement was observed using PCA with data fusion technique. Further work using a hybrid LDA-Competitive Learning Neural Network was performed to validate the fusion technique and classify the samples. It was found that the LDA-CLNN was also improved significantly when data fusion was applied.<\/jats:p>","DOI":"10.3390\/s120506023","type":"journal-article","created":{"date-parts":[[2012,5,10]],"date-time":"2012-05-10T11:11:15Z","timestamp":1336648275000},"page":"6023-6048","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":75,"title":["Improved Maturity and Ripeness Classifications of Magnifera Indica cv. Harumanis Mangoes through Sensor Fusion of an Electronic Nose and Acoustic Sensor"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7108-215X","authenticated-orcid":false,"given":"Ammar","family":"Zakaria","sequence":"first","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ali Yeon Md","family":"Shakaff","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maz Jamilah","family":"Masnan","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fathinul Syahir Ahmad","family":"Saad","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdul Hamid","family":"Adom","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohd Noor","family":"Ahmad","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mahmad Nor","family":"Jaafar","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abu Hassan","family":"Abdullah","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2547-3934","authenticated-orcid":false,"given":"Latifah Munirah","family":"Kamarudin","sequence":"additional","affiliation":[{"name":"Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2012,5,10]]},"reference":[{"key":"ref_1","first-page":"99","article-title":"Influence of Harvest Maturity of Mangoes on Storage Potential and Ripe Fruit Quality","volume":"2","author":"Peacock","year":"1986","journal-title":"ASEAN Food J."},{"key":"ref_2","unstructured":"Pantastico, E.R.B. (1975). Postharvest Physiology Handling and Utilization of Tropical and Subtropical Fruits and Vegetables, The AVI Publishing Company Inc."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1016\/j.foodchem.2008.09.107","article-title":"Cultivar Relationships in Mango Based on Fruit Volatile Profiles","volume":"1","author":"Pandit","year":"2009","journal-title":"Food Chem."},{"key":"ref_4","first-page":"357","article-title":"Ethylene Levels Associated with Fruit and Vegetables during Marketing","volume":"40","author":"Wills","year":"2000","journal-title":"Aust. J. Exp. Agr."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1071\/EA00206","article-title":"Ripening of Climacteric Fruits Initiated at Low Ethylene Levels","volume":"41","author":"Wills","year":"2001","journal-title":"Aust. J. Exp. Agr."},{"key":"ref_6","first-page":"421","article-title":"Development of Electronic Nose Measurements for Mango (Mangifera indica) Homogenate and Whole Fruit","volume":"117","author":"Lebrun","year":"2004","journal-title":"Proc. Florida State Hortic. Soc."},{"key":"ref_7","unstructured":"Salim, S.N.M., Shakaff, A.Y.M., Ahmad, M.N., Adom, A.H., and Husin, Z. (2005, January 21\u201323). Development of Electronic Nose for Fruits Ripeness Determination. Palmerston North, New Zealand."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.postharvbio.2007.09.010","article-title":"Discrimination of Mango Fruit Maturity by Volatiles Using the Electronic Nose and Gas Chromatography","volume":"48","author":"Lebrun","year":"2008","journal-title":"Postharvest Biol. Tech."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/j.postharvbio.2007.06.012","article-title":"Electronic Nose as a Non-Destructive Tool to Characterise Peach Cultivars and to Monitor Their Ripening Stage during Shelf-Life","volume":"47","author":"Benedetti","year":"2008","journal-title":"Postharvest Biol. Tech."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1016\/j.postharvbio.2008.08.008","article-title":"The Aroma Development during Storage of Castlebrite Apricots as Evaluated by Gas Chromatography, Electronic Nose, and Sensory Analysis","volume":"51","author":"Defilippi","year":"2009","journal-title":"Postharvest Biol. Tech."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1166\/sl.2011.1480","article-title":"Magnifera Indica cv. Harumanis Classification Using E-Nose","volume":"9","author":"Zakaria","year":"2011","journal-title":"Sensor Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.biosystemseng.2009.05.004","article-title":"Addressing Potential Sources of Variation in Several Non-Destructive Techniques for Measuring Firmness in Apples","volume":"104","author":"Alegre","year":"2009","journal-title":"Biosyst. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1006\/jaer.1996.0042","article-title":"Sensor for Fruit Firmness Assessment: Comparison and Fusion","volume":"64","author":"Steinmetz","year":"1997","journal-title":"J. Agr. Eng. Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1016\/S0003-2670(02)00107-1","article-title":"Outer Product Analysis of Electronic Nose and Visible Spectra: Application to the Measurement of Peach Fruit Characteristics","volume":"459","author":"Natale","year":"2002","journal-title":"Anal. Chim. Acta"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1007\/s002650050454","article-title":"The Roles of Echolocation and Olfaction in Two Neotropical Fruit-Eating Bats, Carollia perspicillata and C. castanea, Feeding on","volume":"42","author":"Thies","year":"1998","journal-title":"Piper. Behav. Ecol. Sociobiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/S0950-3293(03)00041-7","article-title":"The Impact of Perceptual Interactions on Perceived Flavor","volume":"15","author":"Delwiche","year":"2004","journal-title":"Food Qual. Prefer."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1016\/j.compag.2009.01.006","article-title":"Intelligent Electronic Nose System for Basal Stem Rot Disease Detection","volume":"66","author":"Markom","year":"2009","journal-title":"Comput. Electron. Agr."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.compag.2009.09.019","article-title":"Detecting Stink Bugs\/Damage in Cotton Utilizing a Portable Electronic Nose","volume":"70","author":"Henderson","year":"2010","journal-title":"Comput. Electron. Agr."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"6425","DOI":"10.3390\/s110606425","article-title":"Low-Cost Gas Sensors Produced by the Graphite Line-Patterning Technique Applied to Monitoring Banana Ripeness","volume":"11","author":"Manzoli","year":"2011","journal-title":"Sensors"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"4744","DOI":"10.3390\/s110504744","article-title":"Electronic Noses and Tongues: Applications for the Food and Pharmaceutical Industries","volume":"11","author":"Baldwin","year":"2011","journal-title":"Sensors"},{"key":"ref_21","unstructured":"Cyrano Sciences (2001). The Practical Guide to the Cyranose 320, Cyrano Sciences, Inc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.snb.2009.05.036","article-title":"An Electronic Nose Employing Dual-Channel Odour Separation Columns with Large Chemosensor Arrays for Advanced Odour Discrimination","volume":"141","author":"Taylor","year":"2009","journal-title":"Sens. Actuat. B Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"8782","DOI":"10.3390\/s101008782","article-title":"Improved Classification of Orthosiphon stamineus by Data Fusion of Electronic Nose and Tongue Sensors","volume":"10","author":"Zakaria","year":"2010","journal-title":"Sensors"},{"key":"ref_24","unstructured":"Fryder, M., Holmberg, M., Winquist, F., and Lundstrom, I. (1995, January 25\u201329). A Calibration Technique for an Electronic Nose. Stockholm, Sweden."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4675","DOI":"10.3390\/s100504675","article-title":"Classification of Agarwood Oil Using an Electronic Nose","volume":"10","author":"Hidayat","year":"2009","journal-title":"Sensors"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/0925-4005(91)80185-M","article-title":"Detection of Vapours and Odours from a Multisensor Array Using Pattern Recognition. Part 1: Principal Component and Cluster Analyses","volume":"4","author":"Gardner","year":"1991","journal-title":"Sens. Actuat. B Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1016\/0925-4005(94)87085-3","article-title":"A Brief History of Electronic Noses","volume":"18","author":"Gardner","year":"1994","journal-title":"Sens. Actuat. B Chem."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1109\/JSEN.2002.800688","article-title":"Pattern Analysis for Machine Olfaction: A Review","volume":"2","year":"2002","journal-title":"IEEE Sens. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/S0925-4005(01)00991-1","article-title":"Exploitation of Spatiotemporal Information and Geometric Optimization of Signal\/Noise Performance Using Arrays of Carbon Black-Polymer Composite Vapor Detectors","volume":"82","author":"Briglin","year":"2002","journal-title":"Sens. Actuat. B Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1016\/S0925-4005(03)00543-4","article-title":"Estimation of chemical and physical characteristics of analyte vapors through analysis of the response data of arrays of polymer-carbon black composite vapor detectors","volume":"96","author":"Sisk","year":"2003","journal-title":"Sens. Actuat. B Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"13232","DOI":"10.1021\/la7026708","article-title":"Use of Spatiotemporal Response Information from Sorption-Based Sensor Arrays to Identify and Quantify the Composition of Analyte Mixtures","volume":"23","author":"Woodka","year":"2007","journal-title":"Langmuir"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"5099","DOI":"10.3390\/s90705099","article-title":"Applications and Advances in Electronic-Nose Technologies","volume":"9","author":"Wilson","year":"2009","journal-title":"Sensors"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Rojas, R. (1996). Neural Networks\u2014A Systematic Introduction, Springer-Verlag.","DOI":"10.1007\/978-3-642-61068-4"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Priddy, K.L, and Keller, P.E. (2005). Artificial Neural Networks: An Introduction, SPIE Press.","DOI":"10.1117\/3.633187"},{"key":"ref_35","unstructured":"Hagan, M.T., Demuth, H.B., and Beale, M.H. (1996). Neural Network Design, International Thomson Publishing Inc."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/S1672-6529(07)60013-4","article-title":"Multisensor Data Fusion for High Quality Data Analysis and Processing In Measurement And Instrumentation","volume":"4","author":"Huang","year":"2007","journal-title":"J. Bionic. Eng."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/S0925-4005(02)00313-1","article-title":"Electronic noses Inter-Comparison, Data Fusion and Sensor Selection in Discrimination of Standard Fruit Solutions","volume":"88","author":"Boilot","year":"2003","journal-title":"Actuat. B Chem."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/j.postharvbio.2003.08.007","article-title":"Prediction of Ripe-Stage Eating Quality of Mango Fruit from its Harvest Quality Measured Non-Destructively by Near Infrared Spectroscopy","volume":"31","author":"Saranwong","year":"2004","journal-title":"Postharvest Biol. Tech."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"326","DOI":"10.1016\/j.postharvbio.2006.09.012","article-title":"Prediction of Mango Eating Quality at Harvest Using Short-Wave Near Infrared Spectrometry","volume":"43","author":"Subedi","year":"2007","journal-title":"Postharvest Biol. Tech."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1016\/S0925-5214(02)00117-5","article-title":"Aroma Volatiles Production during Fruit Ripening of \u2018Kensington Pride\u2019 Mango","volume":"27","author":"Lalel","year":"2003","journal-title":"Postharvest Biol. Tech."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/S0021-9673(04)00969-0","article-title":"New Gas Chromatography-Olfactometric Investigative Method, and its Application to Cooked Silurus glanis (European Catfish) Odor Characterization","volume":"1056","author":"Hallier","year":"2004","journal-title":"J. Chromafogr. 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