New test detects coffee impurities with 95% accuracy

A QUICK AND EASY way to identify counterfeit coffee could be in the horizon. Researchers at the State University of Londrina in Brazil have devised a new test using liquid chromatography and statistical tools to detect fillers with 95% accuracy.

The new method allows for a much closer look at the coffee ingredients in an unbiased way, resulting in a more analytical approach. This contrasts with the current methods of distinguishing unwanted additives by checking coffee under a microscope or tasting it, which are subjective rather than quantitative.  

According to research team leader Suzana Lucy Nixdorf, Ph.D., from the State University of Londrina, with coffee being composed of carbohydrates, researchers could develop a “characteristic fingerprint” using chromatography, and this would help in distinguishing the real coffee compounds. The unwanted fillers generate different levels of sugars than the natural ingredients, making them easy to identify.

The test, which was done on ground, roasted coffee in Brazil, would make it possible to know if coffee is pure or has been tampered with corn, barley, wheat, soybeans, rice, beans, acai seed, brown sugar or starch syrup.

The research team is also analysing several fillers that are considered impurities as opposed to adulterants. These impurities can be parts of the coffee plant that are introduced at harvest and are not really supposed to be in the final product. Tests have revealed wood, twigs, sticks, parchment, husks, whole coffee berries and even clumps of earth that are almost the same colour as coffee have been mixed in. Ms Nixdorf said that identifying these impurities is essential because the presence of a large amount might indicate they were added intentionally, not by accident as some producers claim. She added that the problem is that it becomes impossible to see any difference between grains of lower cost incorporated into the coffee after roasting and grinding the raw material, especially with the dark colour and oily texture of coffee.

The growing concern about coffee supply shortage, particularly in regions such as Brazil where droughts and plant diseases are pushing down supply, is giving rise to the need for measures to detect counterfeit coffee. Even though the additives or fillers might not be harmful, they would mean higher prices and increased profits for producers.

Brazil typically produces 55 million bags of coffee a year. Production this year could drop to 45 million bags, or about 42 billion fewer cups, because of extensive drought in January. A study from the U.K.’s Royal Botanic Gardens and the Environment in 2012 reported that 70% of the world’s coffee supply might disappear by 2080 due to conditions brought about by climate change.  

The research conducted by Ms Nixdorf and her team will be presented at the 248^th National Meeting & Exposition of the American Chemical Society (ACS). The world’s largest scientific society with more than 161,000 members, ACS is a nonprofit organisation chartered by the U.S. Congress. It is a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences.

Mr Nixdorf acknowledges funding from the Government of Brazil’s Coordena??o de Aperfei?oamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Financiadora de Estudos e Projetos and Funda??o Araucária- Apoio ao Desenvolvimento Científico e Tecnológico do Paraná Productivity Scholarship.