Abstract

Adulteration of food products remains a food security risk. Spices are food components with a high value per unit mass due to their desired flavour attributes and are therefore economically worthwhile targets for adulteration. Vibrational spectroscopy techniques could be ideal to detect adulterants due to benefits such as speed of analysis. Near infrared (NIR) and mid-infrared (mid-IR) spectra were used to quantify the amount of adulterant (buckwheat or millet) in ground black pepper. NIR spectra used for calibration were the average spectra of individual hyperspectral images recorded with a spatial resolution of 300 mu m x 300 mu m from 1000 nm to 2500 nm at 6.3 nm intervals; hyperspectral images were collected to cope with the heterogeneity of the samples. The calibrations calculated, using the averaged NIR spectra, were more accurate than those calculated from mid-IR spectra. This was a direct result of sample heterogeneity and the insufficient sampling area in the mid-IR measurements. NIR-based calibrations were suitable for process control when the appropriate spectral data pre-treatment was used: standard normal variate followed by first derivative pre-processing of the 1100-2500 nm spectral range resulted in a root mean square error of prediction equal to 2.7% w/w and a ratio of standard error of prediction to standard deviation (validation set) of 11.1.

Keywords

adulteration; black pepper; spice; image prediction; regression modelling; spectral pre-processing

Published in

Journal of Near Infrared Spectroscopy
2012, Volume: 20, number: 5, pages: 521-528
Publisher: N I R PUBLICATIONS

SLU Authors

• Geladi, Paul

  • Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG2 End hunger, achieve food security and improved nutrition and promote sustainable agriculture


UKÄ Subject classification

Other Chemistry Topics


Publication identifier

DOI: https://doi.org/10.1255/jnirs.1008

Permanent link to this page (URI)

https://res.slu.se/id/publ/45069