Development and Characterization of Quinoa Peptide Nanoparticles as Carriers for Bioactive Food Ingredient Encapsulation

Bioactive food ingredients offer significant health benefits. However, their poor water solubility and storage stability often limit their efficacy and practical application. In this study, quinoa peptide nanoparticles (QPNPs) were fabricated by controlled enzymatic hydrolysis, with particle sizes below 100 nm. Their structural stability was primarily maintained through hydrophobic interactions and hydrogen bonding. Caffeic acid phenethyl ester (CAPE) was selected as a model compound to evaluate the encapsulation performance of QPNPs. The results demonstrated that the encapsulation of CAPE was mainly driven by hydrophobic interactions and hydrogen bonding. The CAPE-loaded QPNPs (CAPE-QPNPs) exhibited a uniform particle size (194.1 ± 1.2 nm), high encapsulation efficiency (77.2%), and loading capacity (3.9%), significantly improving the water solubility and storage stability of CAPE. Furthermore, the cumulative release of CAPE in simulated gastrointestinal fluid was only 34% after 4 h, indicating strong resistance to digestion, which may be attributed to the dense shell structure of the nanoparticles. Overall, these findings suggest that QPNPs are a promising delivery system for encapsulating bioactive food ingredients and enhancing their physicochemical stability.