Harnessing pH for sustainable and effective synthesis of phenolic compound-loaded nanoparticles directly from raw plants.

While considerable efforts have been made to develop phenolic compound-loaded nanoparticles for applications in foods, pharmaceuticals, and agriculture, current production methods fall short in sustainability, efficiency, and cost-effectiveness. This study introduces a pH-based "raw-to-nano" strategy to produce phenolic compound-loaded nanoparticles directly from raw plants. Curcumin-loaded nanoparticles were first formulated from raw turmeric, with an average size of 141.3 ± 2.8 nm and a surface charge of -23.3 ± 0.7 mV. Nanoparticles are stabilized by electrostatic interactions at pH 7, but stability decreases under acidic conditions (pH < 5), which could limit certain applications in acidic beverages. Based on pH effects and microstructures, a core-shell model is proposed, where acidic polysaccharides coat the surface, and insoluble branched starches form the inner phase, trapping hydrophobic curcumin molecules. This strategy successfully applies to other plants like ginger, paprika, and thyme, enabling versatile nanoparticle synthesis for practical applications in various aspects.