ARS | Publication request: The use of fatty acid profile as a potential marker for Brazilian coffee (Coffea arabica L.) for corn adulteration

Submitted to: Journal of Brazilian Chemical Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 5, 2008
Publication Date: November 26, 2008
Citation: Jham, G.N., Berhow, M.A., Manthey, L.K., Palmquist, D.E., Vaughn, S.F. 2008. The use of fatty acid profile as a potential marker for Brazilian coffee (Coffea arabica L.) for corn adulteration. Journal of Brazilian Chemical Society 19:1462-1467.

Interpretive Summary: Coffee is the most popular beverage worldwide, with over 400 billion cups consumed each year. Americans consume 400 million cups of coffee per day, or 146 billion cups of coffee per year, making the United States the leading consumer of coffee in the world. Coffee is grown commercially in over 45 countries throughout the world, with Brazil being the largest producer. Although there are several coffee species, only Coffea arabica and Coffea canephora (robusta), or their blends, are used to produce most roasted coffee. Because C. arabica beans have the highest commercial value, due to their pronounced flavor, it is widely speculated that much C. arabica coffee is adulterated with lower priced adulterants, including roasted corn. In this study, we examined whether it was possible to determine adulteration of coffee samples with roasted corn by analyzing the fatty acid (FA) composition of coffee samples. Our results indicate that while we could detect FA differences between pure coffee and pure roasted corn, we could not detect differences between unadulterated and adulterated coffee samples, indicating that FA analysis of coffee cannot be used as a marker of adulteration. These results are of interest to both researchers and coffee manufacturers in order to make methods to detect adulterated coffee samples.

Technical Abstract: Fatty acid methyl ester (FAME) compositions of six coffee (Coffea arabica L.) varieties (Catuaí, Catuca, Burbourn, Mundo Novo, Rubí, and Topázio) known to produce good, intermediate and poor quality coffee were determined for the first time. Average area % of the FAMEs of the six varieties was: palmitic (38.2), stearic (8.3), oleic (8.6), linoleic (38.5), linolenic (1.6), and arachidic (3.6) acids, respectively. The method was very quick with complete characterization (>99%) of the samples studied being possible in less than 6 min. While these values may provide insights for evaluating the coffee quality, no significant effect (p<0.05) of coffee variety was found on area % of the FAMEs. In addition, FAMEs of six corn samples, six commercial coffee brands and one commercial coffee sample intentionally contaminated with three levels of corn were compared. Although the linoleic/stearic ratio were significantly different in coffee and corn FAMEs, these probes could not be used as markers to detect corn adulteration in commercial coffees.