Monitoring of cocoa quality and conching, tempering, cooling processes in chocolate production with FTIR spectroscopy

Abstract

In this study, cocoa quality and process parameters of chocolate production were investigated with ATR-FTIR spectroscopy and chemometrics. Moisture, pH, protein, fat, ash and particle size properties of cocoa samples were correlated with FTIR spectra using the partial least squares (PLS) method to develop a rapid technique. On the other hand, effects of different conching (standard conching, 12 h at 50 degrees C; 24 h at 50 degrees C and 12 h at 60 degrees C; 24 h at 60 degrees C), tempering (24 degrees C, 28 degrees C and 32 degrees C) and cooling (10 degrees C and 15 degrees C) process parameters in chocolate production were monitored with ATR-FTIR. Spectra were evaluated with unsupervised (PCA) and supervised (PLS-DA) chemometric techniques. Results showed that FTIR spectroscopy is a strong tool for rapid quality control of cocoa samples, with R2pred values above 0.95 and RMSEP values below 0.90 for each quality parameter. The results also showed the potential of FTIR spectroscopy for process control, with 100% prediction sensitivity and specificity in PLS-DA models for conching, tempering, and cooling. The technique demonstrated the ability of FTIR spectroscopy to detect minimal process variations, suggesting its utility in industry for identifying improperly processed chocolates and preventing quality defects.