Application of FTIR-ATR Spectroscopy for Quality Mapping and Authenticity Verification of Coffee from Traditional Markets in Padang City, Indonesia

Ensuring the authenticity and quality of coffee is essential, particularly in regions where traditional markets play a significant role in daily trade and consumption. This study explores the application of Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) spectroscopy as a rapid, non-destructive analytical technique to assess the quality and verify the authenticity of coffee samples from traditional markets in Padang City, Indonesia. A set of reference spectra was first established using traceable, original coffee beans. These spectra were then compared to those obtained from market samples using multivariate statistical methods. The analysis revealed notable differences in spectral patterns between the original and market-sourced coffee, indicating potential adulteration or blending practices. These discrepancies suggest that some commercially sold coffee may have undergone mixing with inferior or foreign substances, compromising its quality and authenticity. While FTIR-ATR has proven to be an effective preliminary screening tool, further confirmatory analyses such as chromatographic or metabolomics-based approaches, are recommended to validate the findings. This study highlights the significance of quality assurance in traditional markets and advocates for the incorporation of spectroscopic methods into routine monitoring systems within the coffee supply chain.