The objectives of the study were to evaluate the use of near-infrared (NIR)
spectrometry in measuring the physiological properties of mango fruit, cv.
'Tommy Atkins' and to establish relationships between the nondestructive N
IR spectral measurements and the major physiological properties and quality
indices of mango fruit. These include softening of the flesh, total solubl
e solids content and acidity. Intact mango fruit were measured by reflectan
ce NIR in 1200-2400 nm range. NIR models were developed based on multi-line
ar regression (MLR), principal component analysis (PCA) and partial least s
quare (PLS) regression with respect to the reflectance and its first deriva
tive, the logarithms of the reflectance reciprocal and its second derivativ
e. The above regression models, related the NIR spectra to storage period,
firmness, sugar content and acidity. The best combination, based on the pre
diction results, was MLR models with respect to the second derivative logar
ithms of the reflectance reciprocal. Predictions with MLR models resulted s
tandard errors of prediction (SEP) of 1.223, 0.161, 17.14 and 37.03, and co
efficients of determination of 0.9276, 0.6085, 0.8226 and 0.9380 for TSS, a
cidity, firmness and storage period, respectively. It was concluded that by
using the NIR spectrometry measurement system, in the appropriate spectral
range, it is possible to nondestructively assess the maturity factors of m
ango fruit. (C) 2000 Elsevier Science B.V. All rights reserved.