A non-destructive technique to predict a hardening pericarp disorder in intact mangosteen is proposed by
using near infrared (NIR) transmittance spectroscopy in the wavelength range of 660–960 nm. The study
found that the spectral features of normal pericarp mangosteen and hardening pericarp mangosteen were
different. The averaged spectra and individual spectra of hardening pericarp mangosteen from a calibration
set (N = 560) were used to develop classification models, using partial least squares discriminant
analysis (PLS-DA). A model based on individual spectra obtained better classification. The overall accuracy
of classification for a prediction set (N = 358) was 91%. Out of 179 samples of normal pericarp fruits,
167 were identified correctly, while 159 samples out of 179 samples with hard pericarp were predicted
correctly. The results showed that NIR transmittance spectroscopy can be used to predict hard pericarp
disorder in intact mangosteen fruit accurately