Comparative Analyses of Different Routes to Prepare Cutin Colloidal- and Nano- Particle Dispersions from Tomato (Solanum lycopersicum) Peels

Cutin is a natural plant polyester, a constituent of the cuticle that covers aerial plant surfaces. Following the trends of agricultural and food waste reduction and the growing demand for plant-derived nanomaterials, cutin was extracted from tomato peels, a by-product of tomato processing. Subsequently, dispersions of cutin particles in the nano- and colloidal size range were prepared by pH-dependent precipitation. Four types of the dispersions were obtained, i.e., dispersion from cutin extract-NP E dispersion, dispersions from a solution of different cutin isolates, dialyzed cutin isolate-NP D dispersion, washed cutin isolate-NP W dispersion, and standard cutin isolate-NP S dispersion. Cutin precipitation occurred at <i>pH</i> lower than 7 and cutin dispersions with final <i>pH</i> 3-7 were formed. Zeta potential, particle size, and recovery of four cutin dispersions were investigated. All types of cutin particles bear a negative charge which increases on <i>pH</i> increase from 3 to 7, resulting in decrease in cutin nanoparticle size upon <i>pH</i> increase. In addition to that, the influence of cutin solution concentration and storage time on cutin dispersion particle size was found to be mitigated at <i>pH</i> ≥ 6. Among four dispersions, NP S had the highest cutin nanoparticle recovery at all <i>pH</i>s investigated.