Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques

The quality control for fruit maturity inspection is a key issue in fruit packaging and international trade. The quantification of Soluble Solids (SS) in fruits gives a good approximation of the total sugar concentration at the ripe stage, and on the other hand, SS alone or in combination with acidi...

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Main Authors: Pedro Escárate, Gonzalo Farias, Paulina Naranjo, Juan Pablo Zoffoli
Format: Article
Language:English
Published: MDPI AG 2022-08-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/22/16/6081
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author Pedro Escárate
Gonzalo Farias
Paulina Naranjo
Juan Pablo Zoffoli
author_facet Pedro Escárate
Gonzalo Farias
Paulina Naranjo
Juan Pablo Zoffoli
author_sort Pedro Escárate
collection DOAJ
description The quality control for fruit maturity inspection is a key issue in fruit packaging and international trade. The quantification of Soluble Solids (SS) in fruits gives a good approximation of the total sugar concentration at the ripe stage, and on the other hand, SS alone or in combination with acidity is highly related to the acceptability of the fruit by consumers. The non-destructive analysis based on Visible (VIS) and Near-Infrared (NIR) spectroscopy has become a popular technique for the assessment of fruit quality. To improve the accuracy of fruit maturity inspection, VIS–NIR spectra models based on machine learning techniques are proposed for the non-destructive evaluation of soluble solids in considering a range of variations associated with varieties of stones fruit species (peach, nectarine, and plum). In this work, we propose a novel approach based on a Convolutional Neural Network (CNN) for the classification of the fruits into species and then a Feedforward Neural Network (FNN) to extract the information of VIS–NIR spectra to estimate the SS content of the fruit associated to several varieties. A classification accuracy of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>98.9</mn><mo>%</mo></mrow></semantics></math></inline-formula> was obtained for the CNN classification model and a correlation coefficient of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>R</mi><mi>c</mi></msub><mo>></mo><mn>0.7109</mn></mrow></semantics></math></inline-formula> for the SS estimation of the FNN models was obtained. The results reported show the potential of this method for a fast and on-line classification of fruits and estimation of SS concentration.
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spelling doaj.art-51be2501c48a4ee09063f0522ada6c902023-12-03T14:26:16ZengMDPI AGSensors1424-82202022-08-012216608110.3390/s22166081Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning TechniquesPedro Escárate0Gonzalo Farias1Paulina Naranjo2Juan Pablo Zoffoli3Escuela de Ingeniería Eléctrica, Facultad de Ingeniería, Pontificia Universidad Católica de Valparaíso, Valparaiso 2374631, ChileEscuela de Ingeniería Eléctrica, Facultad de Ingeniería, Pontificia Universidad Católica de Valparaíso, Valparaiso 2374631, ChileDepartamento de Fruticultura y Enología, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago 8331150, ChileDepartamento de Fruticultura y Enología, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago 8331150, ChileThe quality control for fruit maturity inspection is a key issue in fruit packaging and international trade. The quantification of Soluble Solids (SS) in fruits gives a good approximation of the total sugar concentration at the ripe stage, and on the other hand, SS alone or in combination with acidity is highly related to the acceptability of the fruit by consumers. The non-destructive analysis based on Visible (VIS) and Near-Infrared (NIR) spectroscopy has become a popular technique for the assessment of fruit quality. To improve the accuracy of fruit maturity inspection, VIS–NIR spectra models based on machine learning techniques are proposed for the non-destructive evaluation of soluble solids in considering a range of variations associated with varieties of stones fruit species (peach, nectarine, and plum). In this work, we propose a novel approach based on a Convolutional Neural Network (CNN) for the classification of the fruits into species and then a Feedforward Neural Network (FNN) to extract the information of VIS–NIR spectra to estimate the SS content of the fruit associated to several varieties. A classification accuracy of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>98.9</mn><mo>%</mo></mrow></semantics></math></inline-formula> was obtained for the CNN classification model and a correlation coefficient of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>R</mi><mi>c</mi></msub><mo>></mo><mn>0.7109</mn></mrow></semantics></math></inline-formula> for the SS estimation of the FNN models was obtained. The results reported show the potential of this method for a fast and on-line classification of fruits and estimation of SS concentration.https://www.mdpi.com/1424-8220/22/16/6081stone fruitsfruit qualitysoluble solidsnear infrared spectravisible spectraconvolutional neural networks
spellingShingle Pedro Escárate
Gonzalo Farias
Paulina Naranjo
Juan Pablo Zoffoli
Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques
Sensors
stone fruits
fruit quality
soluble solids
near infrared spectra
visible spectra
convolutional neural networks
title Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques
title_full Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques
title_fullStr Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques
title_full_unstemmed Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques
title_short Estimation of Soluble Solids for Stone Fruit Varieties Based on Near-Infrared Spectra Using Machine Learning Techniques
title_sort estimation of soluble solids for stone fruit varieties based on near infrared spectra using machine learning techniques
topic stone fruits
fruit quality
soluble solids
near infrared spectra
visible spectra
convolutional neural networks
url https://www.mdpi.com/1424-8220/22/16/6081
work_keys_str_mv AT pedroescarate estimationofsolublesolidsforstonefruitvarietiesbasedonnearinfraredspectrausingmachinelearningtechniques
AT gonzalofarias estimationofsolublesolidsforstonefruitvarietiesbasedonnearinfraredspectrausingmachinelearningtechniques
AT paulinanaranjo estimationofsolublesolidsforstonefruitvarietiesbasedonnearinfraredspectrausingmachinelearningtechniques
AT juanpablozoffoli estimationofsolublesolidsforstonefruitvarietiesbasedonnearinfraredspectrausingmachinelearningtechniques