Fourier transform near infrared spectroscopy applied to analysis of chocolate

Fourier transform near infrared (FT-NIR) spectroscopy was used to establish calibration equations with the aim of determining sucrose, lactose, fat an d moisture in chocolate. The possibility of using FT-NIR spectroscopy for e valuating rheological properties (viscosity and yield) of chocolate was als o investigated. The concentrations of individual components and the values of viscosity and yield obtained by standard methods were used as reference values, The spectra of 96 chocolate samples were recorded in reflectance mo de in the range of 910-2500 nm using an FT-NIR Nicolet Avatar 360N spectrom eter equipped with the UpDRIFT accessory. The first or second derivative tr ansformation of the original NIR spectra gave the best accuracy, A partial least squares (PLS) algorithm was used to create calibration models relatin g reference values to spectral data, The models were validated using cross- validation, The validation results proved that fat, sucrose and lactose can be predicted with sufficient accuracy, while predicted values for moisture , viscosity and yield are less reliable.