Evidence on the discrimination of quinoa grains with a combination of FT-MIR and FT-NIR spectroscopy

Silvio D Rodríguez; M P López-Fernández; S Maldonado; M P Buera

doi:10.1007/s13197-019-03948-7

Evidence on the discrimination of quinoa grains with a combination of FT-MIR and FT-NIR spectroscopy

J Food Sci Technol. 2019 Oct;56(10):4457-4464. doi: 10.1007/s13197-019-03948-7. Epub 2019 Jul 23.

Authors

Silvio D Rodríguez^{1

2}, M P López-Fernández^{1

2}, S Maldonado^{1

2}, M P Buera¹

Affiliations

¹ 1Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
² 2Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET - Universidad de Buenos Aires, Intendente Güiraldes 2160, Pabellón 2, 4to Piso, Ciudad Universitaria, Buenos Aires, Argentina.

Abstract

Quinoa is considered as a valuable re-emergent crop due to its nutritional composition. In this study, five quinoa grains from different geographical origin (Real, CHEN 252, Regalona, BO25 and UDc9) were discriminated using a combination of FT-MIR and FT-NIR spectra as input for principal component analysis (PCA), cluster analysis (CA) and soft independent modelling class analogy (SIMCA). The results obtained from PCA and CA show a great power of discrimination, with an average silhouette width value of 0.96. Moreover, SIMCA showed an error rate and accuracy values of 0 and 1 respectively with only 4% misclassified samples. A relationship between each principal component and the most important variables for the discrimination were mainly due to vibrations of several oleofins groups (C-H, C-H₂, C-H₃), alkene group (-CH=CH-), hydroxyl group (O-H) and Amides I and II vibrational modes.

Keywords: Chemometric methods; Infrared spectroscopy; Near infrared spectroscopy; Quinoa grains.