Spectroscopy (MIR), chromatography (RP-HPLC) and chemometrics applied to soluble peptides to discriminate the geographic origin of coalho cheese

Abstract

In the present study, the discrimination of the origin of the traditional brazilian Coalho cheese was investigated by means of peptide profiles using a quick method Mid-Infrared Spectroscopy (MIR) compared to Reversed-Phase High Performance Liquid Chromatography (RP-HPLC) and associated with different chemometric analysis. Soluble peptides were extracted from Coalho cheeses obtained from four different mesoregions of Bahia, Brazil, from seven different producing factories. 70 samples were collected within 10 days of manufacture and analyzed using RP-HPLC and MIR. The RP-HPLC indicated five markers peptides for cheese differentiation and the MIR revealed spectroscopic profiles of amides with distinct absorptions, varying according to geographic origin. Using the Principal Component Analysis, the MIR correctly discriminated the peptide profiles of the cheeses by origin, presenting distinct groups in three-dimensional space and the Artificial Neural Networks models were efficient in correctly classifying all cheeses in their respective groups of validation, associated with low error rates (RMSEVRP-HPLC = 0.0165, RMSEVMIR = 0.0488). The results showed that RP-HPLC and MIR discriminated the origin of Coalho cheese and the MIR presented itself as an alternative of lower operational cost, fast, efficient and robust for this investigation.