Influence of Raw‐Material Processing on Gold and Silver Nanoparticles Stability Using Ultrasound‐Extracted Pink‐Pepper Compounds

The ultrasound‐assisted green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs) from Schinus terebinthifolius extracts delivered stable colloids whose physicochemical properties depend on raw‐material preprocessing. Ground sonicated extracts (GSE) produced narrower size distributions and more negative zeta potentials (−19.6 mV for AuNPs, −23.5 mV for AgNPs) than unprocessed sonicated extracts (USE), which favored aggregation, especially at 100°C. Surface‐plasmon resonance (SPR) red‐shifted for AuNPs‐USE, indicating larger particles. High‐resolution transmission electron microscopy (TEM) corroborated these trends: GSE‐derived AgNPs formed 15–40 nm quasi‐spheres, whereas USE yielded fused dendritic assemblies of 20–80 nm subunits; AuNPs ranged from densely coalesced 8–25 nm chains (100°C) to isolated spheres (25°C). Coherent lattice fringes with d = 0.23 nm {1 1 1} and 0.20 nm {2 0 0} confirmed phase‐pure fcc structures, and fringe continuity across AgNP necks evidenced oriented attachment. Collectively, the data show that extract grinding enhances nucleation control, crystallinity, and colloidal stability, providing a scalable route to biogenic AuNPs and AgNPs for biomedical, catalytic, and food‐preservation applications.