Study of Fluorescence Spectrum for Measurement of Soluble Solids Content in Navel Orange

On-line nondestructive estimation of fruit internal quality greatly benefits the consumer and the fruit industry as a whole because it can ensure the safety and processed product consistency. This research was aimed to build prediction model of soluble solids content (SSC) in navel oranges using ultraviolet lamp induced fluorescence technique. Total 254 navel oranges were separated into the calibration set (170 samples) and prediction set (84 samples). The actual SSC of navel oranges were measured using a digital refratometer. A characteristic wavelength range (385-414nm) was found to build a partial least squares (PLS) model for predicting the SSC in navel oranges. The correlation coefficient (r) between the predicted and actual SSC was 0.9161 and 0.8295 for calibration and prediction set, respectively. The root mean square error of calibration (RMSEC) and prediction (RMSEP) set was 1.0797 and 1.4283, respectively. The results showed that fluorescence spectrum can nondestructively determine SSC in fruit.