Quantification of bioactive compounds and antioxidant activity of two cultivars of Arabica coffee

Xavier, M. B.1; Luz, A. C.1; Dutra, J. C. V.1; Batitucci, M.C. P.1. Jamal C.M.2; Silveira, D.3; Rodrigues, P. M.3.
1Universidade Federal do Espírito Santo. Av. Fernando Ferrari, 514, Goiabeiras, CEP: 29075-10, Vitória - ES, Brasil.
2Universidade Federal do Espírito Santo. Av. Marechal Campos, 1468, Maruípe, CEP 29043-900, Vitória - ES, Brasil.
3Campus Universitário Darcy Ribeiro – UnB, Asa Norte, CEP 70910-900, Brasília - DF, Brasil.
[email protected]

Coffee is the second most consumed beverage in the world and has Brazil as the main producer and exporter worldwide. Besides its commercial value, coffee is also known to have phytochemical constituents with antioxidant activity. Compounds with antioxidant potential are linked to the protection of molecules such as proteins, lipids, nucleic acids, among others, being able to aid in the prevention of diseases such as atherosclerosis, Alzheimer and cancer. With this, coffee becomes an important element in the human diet. Their production stages, mainly related to the roast levels, can lead to significant alterations in the contents of these compounds. Based on this, the present study evaluated the ethanolic extract of two cultivars of Arabica coffee, “Catuaí vermelho IAC 99” and “Catucaí amarelo 2SL”, in different levels of processing post-harvest, of the city of Santa Maria de Jetibá – ES, in order to quantify by HPLC-DAD two components in the coffee (chlorogenic acid and trigonelline), besides the analysis of the tannins content by colorimetric test. It was also evaluated the antioxidant activity by four different colorimetric methods, DPPH, ABTS, FRAP and Chelating activity Fe2+, in order to identify the extract with better performance, being able to infer at what stage its consumption is recommended, besides perceiving how it occurs changes of responses during processing. The HPLC-DAD quantification was calculated from the calibration curve of the standard trigonelline and chlorogenic acid in the concentration of μg.mL-1. The tannin content was calculated from the calibration curve of tannic acid in μg.mL-1. For the antioxidant activity tests, the EC50 in μg.mL-1 (n = 3) was calculated. In the statistical analysis, ANOVA was used, followed by the test Tukey (p<0.05) using ASSISTAT beta software 7.7. The results indicate that there is a significant correlation between the antioxidant activities (DPPH, ABTS and FRAP) and tannin contents, however, such correlation was not observed for the concentrations of trigonelline and chlorogenic acid. The chelanting activity Fe2+ showed no correlation with any of the bioactive compounds evaluated. In addition, it is possible to observe that the roasting processes are directly related to a reduction of bioactive compounds of interest and, consequently, the reduction of the antioxidant activity, with the tannin content being more related to this activity. (Financial Support: FAPES)