The increase in consumption of vegan foods has promoted higher production of different plant-based proteins. This study looked at developing a non-invasive and rapid method to determine the authenticity of plant-based protein powders (free of soy, lactose, and gluten), and classify possible adulterants (soya, whey and wheat) in the powders, using FT-NIR (Fourier Transform-Near-Infrared Spectroscopy) and chemometrics. A set of 47 pure plant protein samples were analysed by FT-NIR. A set of 144 adulterated samples were prepared by adding 10, 15, 20, 25, 30, 35 and 40% (w/w) of each adulterant into pure plant-based protein powder samples, and also analysed. The spectra were analysed chemometrically combining one class and multiclass methods, and it was found that this approach could be successfully used in a range of 10–40% of adulteration, to verify the authenticity of the plant-based protein powders and to classify adulterants into soy, whey, and wheat.
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