Visible–Near Infrared Spectroscopy for Nondestructive Prediction of Firmness and Moisture Content in Bronzing-Affected Jackfruit (Artocarpus heterophyllus cv. ‘Tekam Yellow’)

Abstract

Abstract The Malaysian jackfruit industry is increasingly threatened by “jackfruit-bronzing,” a disease caused by Pantoea stewartii subsp. stewartii , which manifests as yellowish-orange to reddish discoloration of the pulp while leaving the rind visually unaffected. The cv. ‘Tekam Yellow’ cultivar is particularly vulnerable, resulting in substantial postharvest losses. This study explores the feasibility of employing visible near infrared spectroscopy (Vis-NIRS) as a non-destructive method to predict internal bronzing through the estimation of rind or flesh firmness and rind, flesh or seed moisture content. Spectral reflectance data were acquired non-destructively from the rind surface of jackfruit, and the resulting spectra were used to predict rind firmness, and moisture content of rind, flesh, and seed tissues. Jackfruits at 10, 12, and 14 weeks after anthesis (WAA) were analyzed within the 500–950 nm wavelength range. Partial least squares regression (PLSR) models were developed and optimized using preprocessing techniques such as Savitzky–Golay smoothing, standard normal variate (SNV), and multiplicative scatter correction (MSC). The best-performing models yielded high determination coefficients for both calibration (Rc²) and validation (Rv²), reaching up to 0.99, with root mean square error of calibration (RMSEC) and validation (RMSEV) values as low as 0.67 N and 0.74% w.b., respectively. Destructive reference measurements were conducted in parallel and analyzed using ANOVA and Fisher’s protected least significant difference (FPLSD) test at p ≤ 0.05. Results demonstrated that Vis–NIRS applied through the rind surface provided reliable prediction of firmness and moisture-related attributes associated with internal bronzing disorder in jackfruit. The developed approach shows strong potential as a rapid and non-invasive technique for early bronzing detection and postharvest quality assessment in jackfruit.

Plant phenotyping relevance

Vis-NIRSによる非破壊的な植物器官の硬度・含水率推定と、内部障害の早期検出モデル開発・検証が研究の中心であるため。

Code and data availability

The supplied blocks describe Vis-NIRS spectral acquisition, PLSR modeling, and reference firmness/moisture measurements for jackfruit, but contain no public dataset, image, code, model, or supplement deposit. Analysis used proprietary software (The Unscrambler X 10.3) and R, with no availability statement or URL. All 1

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