Application of 2D correlation spectroscopy on olive stones acid hydrolysates: Effect of overliming

In order to valorize olive stones we are studying their dilute-acid hydrolysate (DAH) composition, and trying to highlight the effect of the overliming process on DAH composition in order to perform an effective treatment that maximize sugars concentrations (xylose) and minimizes the amount of toxic materials (FF and HMF). An 2231 experimental design was established to describe the effects of three controlled factors with distinct levels: pH (10 and 12), temperature (25 and 60 °C) and detoxification time (15, 30 and 60 min) on the concentration of xylose, FF and HMF. A better understanding of this overliming process was possible by exploring the chromatograms obtained with 2D Correlation Spectroscopy (2DCOS). 2D correlation spectroscopy gave information about the relations that exist between chromatographic peaks and chromatograms. The order in which the constituents vary can be deduced from the sign of peaks in the synchronous and asynchronous matrices, facilitating the interpretation of kinetic studies.