The purpose of this research was to investigate maturity prediction of red flesh dragon fruit based on
non-destructive measures. Specific weight, sphericity, color value L, a, b and light reflectance spectrum
were linearly combined by partial least squares regression (PLSR) analysis. The PLSR models could predict
days after fruit set, weight ratio and total soluble solids relatively well with standard deviation divided by
standard error of prediction (RPD) of 2.86, 2.45 and 2.38, respectively. Date after fruit set, total soluble
solids, total acid, ratio of total soluble solids and total acidity and weight ratio were transformed into
a principal component 1 (PC1) by the principal component analysis and used to represent a single maturity
index. The PLSR model with non-destructive parameters resulted in an improved performance in the
prediction of the maturity index (PC1) with a RPD increase to 3.49. The model could be further simplified
but retained a comparable accuracy by the application of a log (R680/R550) in place of the light reflectance
spectrum.