Multivariate curve resolution - Alternating least squares analysis of the total synchronous fluorescence spectra: An attempt to identify polyphenols contribution to the emission of apple juices

- MCR-ALS applied to total synchronous fluorescence spectra (TSFS) of apple juices.
- Five fluorescent components extracted with different contribution to differently processed apple juices.
- Correlation found between MCR-ALS components and antioxidant properties of juices.

Presently we applied multivariate curve resolution - alternating least squares (MCR-ALS) method for the analysis of front-face total synchronous fluorescence spectra (TSFS) of differently processed apple juices. This analysis enabled extracting of the TSFS profiles of five fluorescent components with distinct spectral characteristics and different contributions to the fluorescence of individual juices. Based on the spectral profiles and quantitative relationship with the chemical parameters describing the antioxidant properties of juices, three of the resolved components may be tentatively attributed to phenolic compounds. The analysis using multiple linear regression (MLR) and partial least square (PLS) regression confirmed better performance of fluorescence for the prediction of the total flavonoid content (TFC) as opposed to the total phenolic content (TPC) and total antioxidant capacity (TAC).This study demonstrated that MCR-ALS decomposition of the TSFS may provide a selective tool for understanding and interpretation of the observed relationships between the fluorescence and the total antioxidant indices of the apple juices.