Physicochemical Characterization and Valorization of Processing Residues from Amazonian Guayusa (<em>Ilex guayusa</em> Loes.) within a Circular Economy Framework: A Case Study of Kallari Cooperative, Ecuador

Ilex guayusa is a culturally significant Amazonian plant cultivated in traditional chakra agroforestry systems. Processing generates substantial residues with potential valorization opportunities. This study quantified and characterized guayusa processing residues from Kallari cooperative (Napo, Ecuador) to identify circular economy applications. Residues were separated by particle size (425 µm, 300 µm, &lt; 300 µm) and analyzed for 20 replicates measuring density, pH, conductivity, moisture, ash, organic matter, fiber, protein, fat, total phe-nols, tannins, caffeine, and thermal properties. Granulometric analysis revealed 67.50 ± 0.94% coarse fraction (&gt;425 µm), 11.94 ± 0.49% intermediate (300–425 µm), and 20.56 ± 0.91% fine (&lt; 300 µm), indicating 32.5% potential rejection. Fine residues showed mean density 0.27 g/cm³, pH 5.85, moisture 6.22%, high organic matter (92.37%), protein (1.61%), fat (6.78%), total phenols (15.70 units), tannins (9.41 units), and caffeine (1.89–2.09%). No significant differences were found between coarse and fine fractions for 12 parameters (p &gt; 0.05). Guayusa residues retain 55–70% of caffeine and substantial phenolic compounds compared to whole leaves, demonstrating potential for food ingredient applications, functional product development, nutraceutical extracts, and bioenergy generation within circular bioeconomy models.