Validation of multivariate calibration models in the determination of sugar cane quality parameters by near infrared spectroscopy

The determination of soluble solids (BRIX), polarizable sugars (POL) and reducing sugars (RS) sugar cane juice by using near infrared spectroscopy (NIR) and multivariate calibration was developed and validated by calculation of figures of merit. Due to the heterogeneity of the samples, first it was necessary to optimize the calibration set by outlier elimination. The figures of merit such as: sensitivity, analytical sensitivity, selectivity, confidence limit, precision (mean, repeatability), accuracy and signal-to-noise ratio were calculated. Feasible results were obtained for BRIX and POL with RMSEP values of 0.28 and 0.42% of juice and precision of 0.02 and 0.08% of juice, respectively. For both BRIX and POL goodness of fit showed correlation coefficients of 0.99. These results indicate that the models developed for BRIX and POL can be used as an alternative to standard procedures in the sugar cane industry.