Assessing firmness in mango comparing broadband and miniature spectrophotometers

Nur Fauzana Mohd Kasim,Puneet Mishra,Rob E Schouten,Ernst J Woltering,Martin P Boer

doi:10.1016/j.infrared.2021.103733

Nur Fauzana Mohd Kasim, Puneet Mishra + Show 3 more

Open Access

https://doi.org/10.1016/j.infrared.2021.103733

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Journal: Infrared Physics	Publication Date: Apr 6, 2021
Citations: 13	License type: cc-by

Affiliation: Wageningen University & Research

Abstract

The aim of this study was to compare a laboratory-based and a pocket-sized near-infrared (NIR) spectrophotometer (SCiO) to predict mango fruit firmness. Three batches of mango fruit were measured to explore batch specific and global models. To gain insight to useful wavelengths important for predicting mango firmness variables, the bootstrapping soft shrinkage (BOSS) variable selection routine was used. Modelling was performed with partial least-squares regression (PLSR). The reference firmness measurements were performed with AWETA acoustic firmness analyser. The SCiO and the laboratory-based instrument showed similar performances predicting the reference firmness in terms of prediction coefficient of determination (R2). However, the root mean squared error of prediction (RMSEP) was slightly lower for the laboratory-based instrument compared to the SCiO, likely because a broader spectral region was used. The performance of the batch specific models was improved by up to 8% in R2 with a 13% reduction in RMSEP when BOSS was applied. For both laboratory based and SCiO, the global models based on combined data from the three batches, showed good performance (R2 0.74–0.93, RMSEP 4.8 – 8.2 Hz2g2/3 depending on the batch) to predict the firmness. Due to comparable performance of the SCiO compared to the laboratory-based spectrophotometer, the pocket-sized SCiO NIR sensor has the potential to become a low-cost, easy to use non-destructive tool to measure firmness in mango fruit.

Highlights

Mango (Mangifera indica L.) holds significant world-wide economic values in terms of production and consumption
This study compared performance of two spectrophotometers to predict mango firmness i.e. a laboratory-based instrument operating in spectral range of 305–1713 nm and a portable spectrophotometer SCiO 740–1070 nm
The results showed that the SCiO performed similar to the laboratory-based instrument in terms of R2p, the root mean squared error of prediction (RMSEP) for the SCiO was slightly higher than the laboratory-based instrument

Summary

Introduction

Mango (Mangifera indica L.) holds significant world-wide economic values in terms of production and consumption (https://www.tridge. com/intelligences/mango/export). In the European as well as global market, the Netherlands plays an important role in mango import and export trade. Mango fruit are imported into the Netherlands and re-exported to the neighboring European countries. The Netherlands market has seen an increase of 88.4% in export trade for mango fruit in the past five years (Tridge, 2018). Firmness is the most widely used quality indicator to determine its readiness for the market [7,25]. Firmness of mango fruit can be measured using a texture analyzer [29]. This practice is destructive, and prevents monitoring of the same fruit repeatedly. The monitoring of same fruit is necessary as it allows making decision of the fruit ‘ready to eat’ stage during the arti ficial ripening process

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