Determination of mango physiological indices by near-infrared spectrometry.
Schmilovitch Z., Mizrach A., Hoffman A., Egozi H., Fuchs Y.
Author Affiliation: Institute of Agricultural Engineering, A.R.O., The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel.
Postharvest Biology and Technology 19 : 245-252
Abstract : The objectives of the study were to evaluate the use of near-infrared (NIR) spectrometry for measuring the physiological properties of mango fruits, cv. Tommy Atkins, and to establish relationships between the non-destructive NIR spectral measurements and the major physiological properties and quality indices of mango fruits. These include softening of the flesh, total soluble solids (TSS) content and acidity. Intact mango fruits were measured by reflectance NIR in the 1200-2400 nm range. NIR models were developed based on multilinear regression (MLR), principal component analysis (PCA) and partial least square (PLS) regression with respect to the reflectance and its first derivative, the logarithms of the reflectance reciprocal and its second derivative. The above regression models related the NIR spectra to storage period, firmness, sugar content and acidity. The best combination, based on the prediction results, was MLR models with respect to the second derivative logarithms of the reflectance reciprocal. Predictions with MLR models resulted in standard errors of prediction (SEP) of 1.223, 0.161, 17.14 and 37.03, and coefficients of determination of 0.9276, 0.6085, 0.8226 and 0.9380 for TSS, acidity, 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 non-destructively assess the maturity factors of mango fruits.