Characterization of peppercorn, pepper oil, and pepper oleoresin by vibrational spectroscopy methods.

NIR-FT-Raman as well as ATR-IR and NIR spectroscopy in combination with efficient chemometric algorithms was applied for rapid determination of piperine in black and white ground pepper and green whole pepper berries as well as pepper oleoresins. Most of the well-resolved Raman signals detected in the spectra of pepper and the related oleoresins can be assigned to piperine, which is known to be the main pungent principle in these products. On the basis of the specific key bands of piperine, also selective Raman mappings were successfully performed to determine the in situ distribution of the alkaloid in the whole green berry and the dried peppercorn as well.

Determination of alkaloids in capsules, milk and ethanolic extracts of poppy (Papaver somniferum L.) by ATR-FT-IR and FT-Raman spectroscopy.

Fourier transform (FT) infrared spectroscopy using a diamond composite ATR crystal and NIR-FT-Raman spectroscopy techniques were applied for the simultaneous identification and quantification of the most important alkaloids in poppy capsules. Most of the characteristic Raman signals of the alkaloids can be identified in poppy milk isolated from unripe capsules. But also poppy extracts present specific bands relating clearly to the alkaloid fraction.

Rapid and non-destructive determination of the echinacoside content in Echinacea roots by ATR-IR and NIR spectroscopy.

NIR reflection and ATR-IR spectroscopy methods are developed to determine the echinacoside content in roots of Echinacea angustifolia and Echinacea pallida. Based on the recorded spectra and the HPLC reference data, chemometrical analyses are performed using a partial least squares (PLS) algorithm. Generally, good calibration statistics are obtained for the prediction of the echinacoside content presenting comparatively high coefficients of determination (R(2)) and low root mean standard errors of cross validation (RMSECV).