Soluble Chenopodin–Alginate and Chenopodin–Chitosan Nanocomplexes as Building Blocks for Food Emulsion Gels

This study evaluates the network-forming and gelation capabilities of quinoa protein (QP) nanocomplexes formed with alginate (QP–Al) and chitosan (QP–C) for the development of structured food emulsion gels and their application in reduced-fat food dressings. Rheological and nanometric characterisation revealed that QP–C complexes exhibited strong shear-thinning behaviour and particle-size instability with increasing concentration, indicating the breakdown of an organised internal network at rest. Conversely, QP–Al showed Newtonian behaviour, smaller particle sizes (~100–250 nm) and high surface charge stability. Upon oil incorporation, the chitosan-based systems underwent an abrupt, concentration-dependent transition from a liquid-like state to a solid-like gel network between 1.2% and 1.6% w/v chitosan. The EQP–C8 gel network exhibited severe structural fragility, degrading into a purely viscous fluid over 28 days. Conversely, the alginate-based system (EQP–AL8) formed a weak physical hydrogel network characterised by a progressive build-up of structure that resisted creaming and maintained structural integrity across temperature changes. EQP–AL8 was successfully used to develop a plant-based, reduced-fat dressing with high organoleptic acceptance; 98% of participants were willing to purchase the product. These findings demonstrate that QP–AL8 provides a clean-label technological path to designing tunable, highly stable food emulsion gels.