Editor's Note
This study combined Near and  Fourier-Transform Infrared Spectroscopy  with chemometrics to screen for the substitution of black pepper with papaya seeds, chili and with non-functional black pepper material such as black pepper husk, pinheads and defatted spent materials. This study shows the huge potential for a fast and rapid screening method that can be used to prove the authenticity of black pepper and detect foreign plant material as well as adulterants from the black pepper plant itself (husk, pinheads and spent).
Abstract
Black pepper  is the most widely used spice in the world. Spices are highly vulnerable to economically motivated adulteration as they are high value products and traded along complex supply chains. The main fraud opportunity is to add cheaper bulking materials. Near and  Fourier-Transform Infrared Spectroscopy  has been combined with chemometrics to screen for the substitution of black pepper with papaya seeds, chili and with non-functional black pepper material such as black pepper husk, pinheads and defatted spent materials. A good separation performance between black pepper and adulterated samples could be shown. After running a binary classification model with an external test set an area under the receiver operator characteristic curve of 0.98 for both, the NIR and FT-IR model was obtained. This study shows the huge potential for a fast and rapid screening method that can be used to prove the authenticity of black pepper and detect adulterants.