Rapid differentiation of coffee bean origin by ketones-based cyclic cataluminescence method

The origin of coffee beans impacts the aroma, flavor, and consumer acceptance, resulting from volatile organic compounds (VOCs) such as ketones, aldehydes, alcohols, pyrazine, and esters. Among them, ketones are associated with the refreshing fruity flavor of coffee beans and can serve as key substances for identifying their origin. Herein, the novel method of cyclic cataluminescence (CCTL) was presented and proven to be feasible for differentiating the origins of coffee beans based on the ketones-involved multiple cataluminescence reactions. A series of exponential decay CCTL peaks were measured through nano Al₂O₃-catalyzed reactions. By fitting the variation of peak intensity I_n with time t, the characteristic attenuation coefficient k was calculated, which can be used to successfully distinguish the origin of the selected coffee beans in combination with chemometrics. The method was validated in the tests of 82 coffee beans. Coffee from the same origin has similar k values, while coffee from different origins has different k values. The discrimination accuracy of linear discriminant analysis and hierarchical clustering analysis was 100 %. The established method was fast. We anticipate that the technique could also serve as a promising new tool for reliably, effectively, and swiftly identifying the origins of other plant products.