Using Near-Infrared Spectroscopy for Non-Destructive Quality Grading of Postharvest Malus domestica Fruits

Advances in Agriculture and Agricultural Sciences | Vol. 12, No. 8, August 2026 | pp. 137–141

DOI: 10.46882/2026.AAAS.120808

Research Article

Title: Using Near-Infrared Spectroscopy for Non-Destructive Quality Grading of Postharvest Malus domestica Fruits

Names of Authors: Nakamura, K.¹, Takahashi, T.¹, and Saito, Y.²

Authors’ Affiliations: ¹Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan. ²National Agriculture and Food Research Organization (NARO), Tsukuba, Japan.

Abstract: Real-time grading of internal quality parameters in apples (Malus domestica) is a core requirement for modern sorting facilities. This research evaluated a non-destructive classification framework utilizing near-infrared (NIR) spectroscopy within the 750–1100 nm spectral window to evaluate Soluble Solids Content (SSC) and flesh firmness values simultaneously. Calibration databases were developed using 350 fruit samples evaluated via partial least squares regression (PLSR) algorithms. The analytical model achieved high accuracy metrics, showing a prediction correlation coefficient (Rp) of 0.92 for SSC and 0.86 for firmness parameters. Root Mean Square Error of Prediction (RMSEP) values were restricted to 0.35 Brix and 0.42 N respectively. Spectral signatures within the 970 nm zone corresponded to internal moisture absorption transitions, whereas the 910 nm band registered carbohydrate structural combinations. Integrating this sensor logic into automated sorting conveyor grids enables high-speed grading separations at line velocities exceeding 5 fruits per second.

Keywords: Sorting technology; Optical sensors; Chemometrics; Apple processing; Non-invasive grading; Sugar content modeling.

Manuscript Timeline: Received May 05, 2026; Revised June 30, 2026; Accepted August 04, 2026; Published August 26, 2026.

Citation: Nakamura, K., Takahashi, T., and Saito, Y. (2026). Using Near-Infrared Spectroscopy for Non-Destructive Quality Grading of Postharvest Malus domestica Fruits. Advances in Agriculture and Agricultural Sciences, 12(8), pp. 137–141.

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