Impact of Spirulina Extract-Loaded Quinoa Protein Isolate Nanoparticles on the Quality and Stability of Functional Set Yoghurt

Protein and active compounds play a key role in maintaining human health as functional nutrients and as tools in structuring enhanced food products quality. This study explored the potentials of novel quinoa protein isolate nanoparticles (QPI-NPS) loaded with spirulina ethanol extract (SE) with different concentrations (0.2, 0.4, and 0.6%), and its impact on enhanced properties assessing; chemical, physical, functional and sensory attributes of set yoghurt on time intervals up to 21 days of cold storage. Characterization of the (QPI-NPS) using dynamic light scattering (DLS) revealed particle sizes ranging from 219.90 to 720.40 nm and the polydispersity indices (PDI) was between 0.270 and 0.386, with transmission electron microscopy (TEM) defining nanoparticle microstructure formation. Encapsulation efficiency reached a maximum of 89.75%. High-Performance Liquid Chromatography (HPLC) analysis identified gallic acid, chlorogenic acid, catechin, methyl gallate, naringenin, and quercetin as dominant phenolic compounds in SE and quinoa flour (QF). Results indicated that incorporating 0.4% spirulina extract quinoa protein isolate nanoparticles (SE-QPI-NPS) optimized particle size, stability, homogeneity, and encapsulation efficiency. The QPI-NPS fortification resulted enhanced the fortified yoghurt chemical, viscosity, antioxidant potentials and sensory attributes. This study highlights the promising applications of novel QPI-NPS as a delivery vehicle for spirulina extract, improving the functionality and consumer acceptability of functional food products.