Rapid Spectroscopic Analysis of Marzipan—Comparative Instrumentation

This study had the dual purpose of applying vibrational spectroscopy to measure marzipan composition and of comparing a number of infrared and near infrared (NIR) set-ups and sampling techniques. A set of 32 marzipan samples of nine different recipes were analysed chemically and measured on six different spectrometer set-ups. Calibrations were developed using partial least squares regression (PLSR) to moisture and sugar content. Interval PLS (iPLS) was applied to all the recorded data sets to find optimal spectral intervals (of 100 nm) for the calibrations. The root mean square error of cross-validation (RMSECV) for the prediction of the moisture was found to be 0.36% w/w moisture (range 7–19%). The sugar content was predicted with a RMSECV of 1.43%w/w(range 33–68%). Despite large variations in spectral range, instrumental design and sampling devices the different NIR spectrometer set-ups yielded calibration results with only small differences. The results are discussed in terms of the robustness of NIR instrumentation for rapid non-destructive food analysis and underline the holistic information provided in the NIR spectral range.