Mathematical model for predicting coffee roast degree using spectral reflectance characteristics from the AS7265X sensorDiang Sagita, Sutrisno Suro Mardjan, Slamet Widodo, Suparlan Suparlan and Pradeka Brilyan PurwandokoBIO Web Conf., 199 (2025) 01001DOI: https://doi.org/10.1051/bioconf/202519901001