Background: Laboratories that carry out food analysis need well-characterized reference materials to improve the accuracy of information given on product labels to help consumers choose a product. In some countries there are no regulations concerning the quality and authenticity of roasted and ground coffee. Consequently, reference material needs to be able to identify and ratify different percentiles in coffee blends to support possible legislation and obtain standard labeling.
Objective: The aim of this project was to prepare reference material for roasted and ground blends from Coffea arabica and Coffea canephora.
Methods: The green coffee beans were roasted at 240 °C for 14 minutes and ground (< 600 µm); then the reference materials were homogenized by a “Y” homogenizer for 6 uninterrupted hours. The reference material consisted of blends of C. arabica and C. canephora, respectively: 100:0; 95:5; 75:25; 50:50; 25:75; 5:95 and 0:100 %. The weight loss during the roasting was recorded, the instrumental color was analyzed, and the size and distribution of particles were evaluated with a diffractometer.
Results: The reference material presented homogeneity regarding particle size and distribution, and weight loss. The C. canephora content in the blend increased the degree of luminosity (CIEL*) and tendency to yellow (CIEb*). The blend presented a tendency to red (CIEa*) as the proportion of C. canephora increased.
Conclusion: The development of these reference materials can offer parameters for other similar reference materials and to stimulate legislation for commercial coffee labels and their compliance by the appropriate supervisory bodies.
Keywords: coffee, blends, Coffea arabica, Coffea canephora, reference material, authenticity
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