What’s in My Coffee? Do-It-Yourself Testing for Chicory Adulteration Using Particle Trapping in Stencil-Based Paper Devices

Our study introduces a cost-effective Do-It-Yourself (DIY) method for detecting chicory adulteration in coffee powder via the Shake & Invert approach integrated with a particle trapping mechanism. Coffee powders of different sizes were blended with chicory in distinct proportions. A bioline layer was employed as an adhering agent to selectively capture chicory on a laminated paper-based device. This selective adhesion is attributed primarily to the differences in surface morphology between the coffee and chicory particles. The texture and structural arrangement of the particles play crucial roles in determining their interaction with the bioline-coated surface. SEM imaging provided further insight into these differences, revealing that chicory possesses rough and distinctive fiber-like structures, whereas the coffee particles have a uniform plate-like surface. These structural characteristics are believed to enhance its adhesion toward the bioline-coated paper, resulting in superior adhesion compared with that of the coffee particles. Our developed approach exhibited a limit of detection (LOD) at a coffee-to-chicory ratio of 90:10. This understanding of the distinct physical properties of chicory and coffee underscores the effectiveness of our adhesive testing method, indicating its potential as a robust tool for detecting chicory within 5 min. This “low-cost” sensing could facilitate accessible screening of coffee samples, enhancing quality within the industry and ultimately safeguarding consumer interests.