Production of high internal phase emulsions using sesame protein isolate nanoparticles as natural Pickering stabilizers

This research investigates the production of sesame protein isolate nanoparticle (SPIN) derived from sesame seed cake, an agricultural byproduct, through thermal treatment and salt-induced gelation, for the formulation of high internal phase Pickering emulsions (HIPPE), contributing to promote sustainable food waste management. Nanoparticles were characterized in terms of particle size, zeta potential, and microstructure. SPIN sizes ranged from 171 to 318 nm and showed a more hydrophobic surface than sesame protein isolate. FTIR analysis revealed hydrogen bonding and hydrophobic interactions within SPIN. TEM images showed a cross-shaped structure with a rough surface, unlike the spherical shape of the sesame protein isolate. The effect of SPIN concentration on HIPPE stability was examined. Increased nanoparticle concentration reduced droplet size and interfacial tension while enhancing stability against coalescence and creaming. A higher storage modulus than loss modulus indicated semi-solid, gel-like structures. Confocal laser scanning microscopy showed HIPPE stabilization by a dense network surrounding the oil droplets. Morphology and droplet size of HIPPE were studied at 0.5 %, 1 %, and 2 % SPIN over 28 days. Increasing SPIN concentration reduced droplet size and improved uniformity and the results indicated that SPIN concentration of 2 % led to production of HIPPE with small and stable oil droplets (37.8 ± 1.2 μm) after 28 days. Higher SPIN levels also transformed emulsions into semi-solid forms, reducing coalescence. These findings highlight the potential of food and agricultural byproducts as novel Pickering stabilizers. Moreover, the developed HIPPEs present a promising alternative to partially hydrogenated oils by maintaining product quality. • SPIN produced from sesame seed cake using heat and salt-induced gelation. • SPIN nanoparticles (171–318 nm) showed improved hydrophobicity and stability compared to SPI. • HIPPEs (80 % oil) stabilized by SPIN resisted coalescence and thermal stress. • SPIN improved HIPPE droplet morphology and stability during 28-day storage.