Tavares L. A., Ferreira A. G., Ferreira M. M. C., Correa A, Mattoso L. H., "Analysis of blends of raw coffees of Arabica and Robusta varieties through 1H NMR and chemometric methods". Copenhagen, Denmark, 13-15/09/2004: 7th International Conference on Applications of Magnetic Resonance in Food Science: The multivariate challenge. Book of Abstracts, (2004). Poster 24.
24 - BLENDS ANALYSIS OF ARABICA AND ROBUSTA RAW COFFEES
SPECIES THROUGH 1H NMR AND CHEMOMETRIC METHODS
Leila Aley Tavares1,
Elisangela Fabiana Boffo1, Antonio Gilberto
Ferreira1, Márcia Miguel Castro
Ferreira2,
Luiz Henrique
Capparelli Mattoso3, Alessandra Alves Corrêa3
1UNIVERSIDADE
FEDERAL DE SÃO CARLOS, 2UNIVERSIDADE
DE CAMPINAS, 3EMBRAPA, BRAZIL
The drink coffee is prepared from arabica or robusta variety grain, or even from blends of them. Arabica variety presents flavor more pronounced and refined, so it can get a best price than robusta in the international trade. This increase the chance of frauds and require techniques that have power to discriminate both varieties in a blend. In this work was used chemometric methods and 1H NMR spectroscopy data to discriminate arabica and robusta blends as much as classificatory and quantitative analysis. The 1H NMR data were aquire in BRUKER 9.4 Tesla equipment and all measurements were done in triplicate. Were used eleven coffee samples without roast and with different contents of arabica and robusta specie. The chemometric methods used were: PCA and HCA for exploratory analysis, KNN and SIMCA for classificatory analysis, PCR and PLS for quantitative. Results obtained showed that the methods of exploratory and classificatory analysis can group the blend samples correctly in two groups, one content less and the other high proportion of arabica specie. However the method KNN shows be better than SIMCA because it can discriminate the samples in two groups (arabica and robusta) without any error using ten neighbours. To predict the proportion of each variety in the coffee blend were used PLS and PCR methods and PLS showed better than the PCR. The same were done with roast coffee sample but the results were not so good because the roast degree made a strong influence in the chemometric analysis.