Photoaging represents the primary exogenous contributor to skin aging, triggered by ultraviolet exposure. It compromises skin barrier integrity, disrupts elastic fibers, accelerates collagen breakdown, and intensifies oxidative stress. Collagen hydrolysate shows great potential in addressing photoaging owing to its distinctive bioactivity, favorable safety profile, convenience, and economic viability. This review comprehensively examines the anti-photoaging mechanism of collagen hydrolysate: by modulating critical signaling pathways (transforming growth factor-β (TGF-β), mitogen-activated protein kinase (MAPK), nuclear factor erythroid 2 related factor 2 (Nrf2), and nuclear factor kappa-B (NF-κB)), it promotes extracellular matrix homeostasis, mitigates oxidative stress, inhibits inflammation, diminishes hyperpigmentation, and indirectly regulates the gut-skin axis, thereby counteracting photoaging damage. To overcome technical hurdles in the oral administration of collagen hydrolysate, including extensive gastrointestinal degradation and poor targeting efficacy, we summarize the strategies currently used for enhancing the absorption of collagen hydrolysate, highlighting research advances in co-delivery approaches, polysaccharide-based vehicles, and liposomal systems that enhance collagen hydrolysate bioavailability. In view of the existing research limitations, we give an outlook on future research directions and development trends to provide a theoretical basis for the development of collagen-derived functional foods and their deep application in photoaging prevention and management.

Herein, curcumin (Cur) was encapsulated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles to improve the water solubility of Cur, and the formulation was optimized by single factor experiments. The surface of PLGA nanoparticles was modified by human transferrin (Tf) to improve the absorption efficiency of active substances by intestinal cells. Our findings indicated that the optimal preparation method for Cur-PLGA-NP was solvent volatilization and mixing the oil phase with the aqueous phase at a volume ratio of 1:2.5, the optimal loading ratio was 1:15, and the optimal mass concentration of emulsifier F68 was 0.3%. The uptake of Tf-modified PLGA nanoparticles (Tf-NP) by human colon cancer cell line HT-29 cells was significantly higher than that of the control, indicating that both the loading efficiency of Cur and its absorption by intestinal cells were significantly improved by using Tf-NP as a delivery vehicle for Cur. In summary, the absorption efficiency of Cur can be improved by modifying Cur-loaded PLGA nanoparticles with Tf, which provides a reference for the design of delivery systems for active substances with poor water solubility.

Water-in-water emulsions, which have a very low interfacial tension and a thick interfacial layer, are formed by two thermodynamically incompatible hydrophilic macromolecules in a certain proportion. It has been reported that the system cannot be stabilized by surfactants, but can avoid macroscopic phase separation by gelation of one or two phases. Recently, it has been found that the stability of water-in-water emulsions can be improved by the irreversible adsorption of solid particles at the interface based on the stabilization mechanism of oil-in-water Pickering emulsions. In this review, we summarize recent advances in research on the stabilization of water-in-water emulsions, and focus on the stability of Pickering emulsions stabilized by solid particles and its influential factors, as well as its applications in the food field. It is expected that this review will provide new ideas for food structure design based on the stabilization of water-in-water emulsions.

Yoghurt has high nutritional value and health-promoting functions; however, its quality defects such as whey syneresis and poor coagulation affect the sensory experience of consumers. Researchers commonly use food macromolecules to improve the gel stability and sensory properties of yoghurt by modifying the formation of gel networks or inducing the gelation of milk protein. In this review, we summarize the texture defects of yogurt, the factors influencing them, and the strategies to improve the gel stability of yogurt as well as the underlying mechanism. Also, we discuss future trends. This review will provide important guidance for improving the quality and stability of yoghurt products.

Pickering emulsions represent a novel type of emulsion that employs solid particles as stabilizers. Solid particles can be tightly arranged at the oil-water interface by irreversible adsorption to form a monolayer or multilayer film, providing a spatial physical barrier for droplets. Compared with traditional emulsions, Pickering emulsions have attracted wide attention due to their advantages of high stability, low toxicity and low cost. The stability of Pickering emulsion is affected by many factors, such as solid particle properties, concentration, pH and preparation method, etc. Among them, the morphology of solid particles is one of the important factors that determines the interface adsorption behavior and the stabilization ability of emulsion. The different morphology of the solid particles leads to different ways of stabilizing the emulsion at the oil-water interface, mainly includes electrostatic interaction, capillary force, and mutual entanglement to form three-dimensional network structure. However, there is currently no systematic summary on the effects of solid particles with different morphologies on the interfacial adsorption characteristics of Pickering emulsions. Based on this, this review summarized the types of solid particles with different morphologies used to stabilize Pickering emulsions at home and abroad in recent years, including spherical, rod-like, thread-like, flaky, cubic, nanotube, dumbbell, ellipsoid and disc-like, etc. It focused on their interfacial adsorption properties for stabilizing Pickering emulsions, such as adsorption activity, arrangement and assembly behavior, inter-particle interactions and emulsion viscosity, etc. Based on the special interfacial adsorption properties of Pickering emulsions, the applications of Pickering emulsions in food fields such as active component encapsulation and delivery, lipid substitution, interfacial catalysis, antimicrobial and so on were reviewed. Furthermore, the study discussed the problems in the study of Pickering emulsions stabilized by non-spherical solid particles, and analyzed the development potential for active component encapsulation and delivery. The review provided the reference for the in-depth research and application of Pickering emulsions stabilized by solid particles with different morphologies.

Artemisia sphaerocephala Krasch. polysaccharide (ASKP) is a novel plant polysaccharide. In this study, an aqueous two-phase system (ATPS) consisting of gelatin (Gel) as the dispersed phase and ASKP 60P (a high-molecular-mass fraction of ASKP) as the continuous phase was constructed based on the thermodynamic incompatibility between 60P and Gel at a specific pH, and Gel/60P ATPS emulsion gels were obtained by introducing Fe³⁺ into the ATPS in order to induce 60P cross-linking. The results showed that the ATPS, consisting of 0.1%–0.5% Gel and 0.5%–1.5% 60P (m/m), exhibited discrete phase separation. The emulsion gel with 0.6% Gel, 1.5% 60P and 60 mmol/L Fe³⁺ showed good gel strength and elasticity. This was attributed to the fact that the increase in Gel concentration led to a decrease in the volume proportion of the continuous phase, resulting in exposure of more Fe³⁺ crosslinking sites, enhancing the interaction between 60P and Fe³⁺, and improving the mechanical properties of emulsion gels. Therefore, this study proposes a new strategy to improve the properties of ASKP gels, which is favorable for the wide application of ASKP in the food, biological and other fields.