Chemometric evaluation of adulteration profile in coffee due to corn and husk by determining carbohydrates using HPAEC-PAD.

The detection of impurities in coffee samples already roasted and ground is a constant concern mainly in order to verify the incidence of frauds. Carbohydrates contents are important as variations on original constitutes of different matrixes may be able to reveal the final composition of the product. In this sense, a study is performed in this paper in order to evaluate the quality through concentration of total carbohydrates in Arabic roasted and ground coffee. Chemometric methods were applied in order to verify an adulteration pattern by coffee husk and corn, by the mixture of different amounts of these contaminants to coffee, following a statistical design of Simplex-Centroid. It could be concluded that this method was efficient in distinguishing different matrixes. In pure coffee, higher concentrations were found for galactose and mannose with levels of 8.25% and 9.65% (w/w), respectively. However, in the pure husks, the main carbohydrates were mannitol (with a level of 0.64%), arabinose (with 4.24%), and xylose (with 3.40%). For the corn sample, glucose was detected in greater quantity, with 52.53% (w/w). Models presenting the influence of adulterants incorporated to coffee in the carbohydrate level were obtained.