An Easy-to-Use and Cheap Analytical Approach Based on NIR and Chemometrics for Tomato and Sweet Pepper Authentication by Non-volatile Profile

Organic products or products with a protected designation of origin (PDO) are vulnerable to fraud; therefore, new and cheaper analytical tools are needed to authenticate them. This work aimed to evaluate the feasibility of using a low-cost and easy-to-use near-infrared (NIR) spectrometer to discriminate agronomic practices and the geographic origin of tomatoes and sweet peppers from different Brazilian regions. Different chemometric approaches were applied, such as principal components analysis (PCA), data driven-soft independent modeling of class analogy (DD-SIMCA), and partial least squares-discriminant analysis (PLS-DA). PCA did not allow clear differentiation between the classes, while the PLS-DA showed excellent classification, with prediction accuracy between 61.9 and 100%. Furthermore, the DD-SIMCA proved to be a good tool for verifying the authenticity of organic tomatoes and sweet peppers, with an accuracy of over 82.7%. These results suggest that the NIR technique combined with chemometrics can be an excellent technique to verify the authenticity of tomatoes and sweet peppers according to the agronomic mode of production and the geographical origin of products by the non-volatile profile using equipment that can be easily set up and acquired at a lower cost.