UV spectroscopy and multi-product multivariate calibration in the determination of the total acidity in industrialized juices

Resumo

The determination of the total acid using UV spectroscopy and multi-product multivariate calibration is presented as an alternative to the conventional method through potentiometric titration. The model was developed including different products (fruit nectar of different flavors and light fruit nectar) where outliers samples were identified and excluded. Partial least squares (PLS) regression was used in order to build the model. Accuracy, represented by the values of the Root Mean Squared Errors of Calibration (RMSEC) and Prediction (RMSEP) were 0.0641 and 0.0534 mg/100 mL, respectively. The confidence ellipse confirms that accuracy was achieved at 99 % confidence, while residues showed random behavior, confirming linearity for the model developed. The proposed methodology shows advantages as fastness, does not requires sample preparation and does not generate toxic waste, being an alternative to the conventional method based on potentiometry.

DOI: 10.14685/rebrapa.v6i1.177