Phlorizin–diosmetin supramolecular hybrid hydrogel: Structural design, functional properties, and applications in dairy thickening

As consumer demand for functional dairy products continues to rise, there is growing interest in formulations that provide both nutritional value and added health benefits. In this study, a novel supramolecular hybrid hydrogel was developed from phlorizin (PHL) and diosmetin (DIO), two natural bioactive flavonoids, to enhance the texture and antioxidant properties of dairy products. The hydrogel was formed via co-assembly through non-covalent interactions such as hydrogen bonding and π-π stacking. Optimized at a 1:2 PHL:DIO molar ratio and 2 % concentration, the hydrogel exhibited improved solubility, thermal stability, and mechanical strength, with a storage modulus exceeding 2.8 kPa, pronounced shear-thinning behavior (viscosity 976,000 to 330 mPa·s at 0.1–10 s⁻¹), and rapid self-healing (103 % recovery). In vitro antioxidant assessments showed significantly enhanced activity compared to individual flavonoids, including 74.43 % DPPH, 57.65 % hydroxyl radical, 80 % ABTS, and 94.92 % superoxide anion scavenging. In vivo experiments using Caenorhabditis elegans demonstrated improved locomotion, a 28.6 % extension in lifespan under oxidative stress, and a 9-fold reduction in ROS levels. When applied in dairy systems, the hydrogel increased milk viscosity by 230-fold at low shear (0.5 % w/v) and improved yogurt texture, achieving 98.89 % water-holding capacity while promoting beneficial Lactobacillus growth. These findings highlight the potential of this dual-function hydrogel as a natural, multifunctional additive for enhancing both the sensory quality and health value of dairy products.