High Specific Surface Areas and Interconnected Pore Networks of Porous Pectin Particles for Enhancement of Protein Adsorption Capacity

The aging population is leading to an increasing demand for nutritional supplements, including functional foods. Functional foods aim to provide essential nutrients and proteins to the human body. Porous particles, specifically macroporous particles with pores size larger than 50 nm, have emerged as promising carrier materials for efficient delivery of bioactive compounds. While macroporous particles have been developed from various inorganic and organic materials, their application to natural polymer-derived materials remains unexplored.<br/>This study focuses on the synthesis and characterization of porous pectin particles, utilizing a template-assisted spray drying method combined with a chemical etching process to prevent thermal decomposition of the natural polymer. Calcium carbonate (CaCO₃) was used as templates to investigate the formation of porous structures. The incorporation of CaCO₃ significantly increased the specific surface area and pore volume, with the porous pectin particles offering interconnected pore networks for penetration and binding. The porous particles had the large specific surface area (171.2 m² g^-1), and 114 times compared with non-porous particles prepared without CaCO₃ particles (1.5 m² g^-1). The study also explored the application of porous pectin particles in protein adsorption using lysozyme as a model protein, providing insights into the adsorption kinetics and isotherm parameters. By comparing the adsorption kinetics of different materials, it was found that increasing CaCO₃ concentrations led to enhanced specific surface areas and total pore volumes, thereby promoting protein adsorption capacity. All porous pectin particles performed rapid adsorption and high uptake capacity on lysozyme, in which PPT-C has the highest adsorption capacity of 2621 mg lysozyme/g adsorbent for the same amount of adsorbent particles. The adsorption isotherm analysis confirmed the formation of a monolayer following the Langmuir model.<br/>In summary, this report highlights the synthesis of porous pectin particles using a template-assisted spray drying method with CaCO₃ templates. Since this technique is rapid, continuous, reproducible, and one-step, it is attractive both in laboratories and in the industrial setting. Thus, it shows significant promise for developing materials on a large-scale in the future. The porous pectin particles exhibited increased specific surface areas compared to pure pectin particles. Notably, the porous pectin particles utilizing CaCO₃ templates displayed excellent lysozyme adsorption capacity, making them promising adsorbents for various applications such as protein and antibodies purification, virus capture, and micro- and nanoplastic recovery from the environment.