In February 2020, Coffea arabica L. grown on the coast and in the Southern Sierra Madre of the state of Oaxaca, Mexico obtained the denomination of origin. Which does not have data on color and chemical composition, the first associated with the degree of roasting and the second with lipids (17-18%), as the group of compounds responsible, in part, for flavor, consistency, and may contribute to health benefits. In the present work, color was determined on the CIE L*a*b* scale and the unsaturated fatty acids by Nuclear Magnetic Resonance (NMR) of 1H and 13C in samples of medium roasted specialty coffee from the "Pluma" coffee-growing region, Oaxaca, Mexico. The average value of L* luminosity in ground coffee was 42.1 ± 0.1 reported for a light roast. Unsaturated fatty acids were quantified from the lipid fraction of the gr1 ound grain by NMR 1H and 13C, obtaining on average the highest abundance of linoleic (41.7 ± 0.5 by 1 H and 41.24 ± 0.5 by 13C), followed by oleic (9.2 ± 0.2 by 1H and 7.4 ± 0.2 by 13C) and linolenic (1.5 ± 0.1 by H and 1.1 ± 0.2 by 13C). This study indicates that 1H and 13C NMR spectroscopy is a useful tool for the quantification of linolenic, linoleic, and oleic fatty acids by the method of key signal shifts of these acids found in lipid samples in roasted coffee grains.
Keywords: Coffea arabica L.; NMR; Oaxaca; unsaturated fatty acids.