Surface modification of zein with Baneh (Pistacia atlantica) gum: Synthesis and characterization of complexed nanoparticles

Zein, a hydrophobic and water-insoluble prolamin protein derived from corn, is widely used in biomedical and food applications due to its amphiphilic nature, biocompatibility, and biodegradability. However, its limited dispersibility and colloidal instability in aqueous environments limit its broader utility. In this study, zein–Baneh gum (BG) nanoparticles (ZBGNPs) were synthesized via the antisolvent precipitation method to improve colloidal behavior and surface performance. BG , a natural polysaccharide extracted from Pistacia atlantica subsp. kurdica, was incorporated as a stabilizing and surface-modifying agent to improve the aqueous behavior of zein. Physicochemical characteristics were investigated using DLS, FTIR, CA, FE-SEM, AFM, DSC, TGA, and XRD. Among the tested formulations, ZBGNPs-0.23 (zein: BG = 1:0.23) showed the most favorable profile, with an average size of ∼40 nm, PDI = 0.1, a zeta potential of +37 mV, and a contact angle of ∼90°, indicating enhanced colloidal stability and balanced wettability. Interestingly, despite its inherently negative surface charge (−8 mV), BG induced an increase in the positive zeta potential of zein nanoparticles. This phenomenon reveals BG as the first reported plant-derived polysaccharide capable of enhancing the positive surface charge of zein, a property previously observed only with synthetic or cationic polymers such as chitosan. This feature broadens ZBGNPs’ applicability, particularly in antimicrobial, mucoadhesive, and targeted delivery systems. Moreover, dual glass transition temperatures (135 °C and 195 °C) suggested phase-separated amorphous domains, while thermal degradation analysis confirmed comparable stability and biodegradability to native zein, with 91.54% total mass loss. These results demonstrate that BG can serve as a multifunctional, locally cost-effective biopolymer for fabricating stable, acid-tolerant, and biocompatible zein-based nanocarriers.