Hydrophobic functional colorants have garnered significant attention in the development of functional foods due to their bioactive properties, such as antioxidant, anti-inflammatory, and metabolic regulatory effects. However, their low solubility in water and environmental instability severely limit their applications. This paper systematically reviews stabilization and solubilization technologies, including cyclodextrin inclusion, microemulsion solubilization, nanoemulsion, biopolymer nanoparticles, and cocrystals, which can enhance pigment dispersibility and stability by reducing interfacial tension or constructing hydrophobic microenvironments. Studies show that cyclodextrin inclusion, microemulsion solubilization, and nano-delivery systems can significantly improve the solubility and stability of hydrophobic colorants. Cyclodextrin inclusion technology improves the solubility of pigments such as curcumin by several orders of magnitude through host-guest molecular interactions; microemulsion systems effectively inhibit photodegradation of light-sensitive colorants (e.g., lutein); nano-structured lipid carriers provide excellent protection against degradation under high temperatures and long-term storage; cocrystal technology and combined delivery strategies (e.g., reverse micelle microemulsion-cyclodextrin systems) serve the dual functions of solubilization and controlled release. Current research has overcome the limitations of the separate application of various technologies, and multi-technology integration has become an effective pathway to enhance the bioavailability of colorants. Future research should focus on the development of green, low-energy technologies and explore multi-technology integration strategies to promote the widespread application of hydrophobic functional colorants in high-value functional products and sustainable cosmetics.

Phytochemicals refer to the bioactive substances present in plants that show specific health-benefiting effects. Due to the poor water solubility, low gastrointestinal stability, low absorption efficiency via intestinal epithelial cells or lymphatic transport, and fast metabolic rate, some phytochemicals exert limited health effects in vivo when orally consumed. Emulsion-based delivery systems can enhance the health effects of phytochemicals in the following ways: 1) by increasing their solubility and stability in the gastrointestinal tract, and preventing them from directly contacting the gastrointestinal environment so as to reduce the degree of degradation; 2) by forming micelles through the oil phase during intestinal digestion to enhance the solubility of lipid-soluble substances in the digestive tract and then improve the absorption efficiency through blood and lymphatic transportation; 3) by regulating the time-delayed release and specific adhesion behavior of phytochemicals in the digestive tract, and changing the structure and function of the intestinal flora or regulating the release and absorption target of phytochemicals to improve their interaction with the intestinal flora. In this paper, the characteristics and advantages of various emulsion systems are reviewed, with special focus on the solubilizing effect of emulsion-based delivery systems on phytochemicals and the effect of emulsion-based delivery systems on their controlled absorption in the digestive tract and interaction with the intestinal flora.

The absorption-enhanced colon-targeted delivery system is a novel colon-targeted delivery system with outstanding colonic adhesion capacity and enhanced colonic absorption function. Compared with the traditional colon-targeted delivery system, it has some advantages such as precisely control of release sites and action time, increased specific surface area and enhanced targeted adhesion efficiency. In this paper, we review the literature on absorption-enhanced colon-targeted delivery systems in terms of their types, structures and preparation methods as well as substances that can be delivered using them, and we summarizes the in vivo and in vitro evaluation methods for absorption-enhanced colon-targeted delivery systems. Moreover, we give an outlook on the current and potential applications of absorption-enhanced colon-targeted delivery systems. Through this review, we conclude that absorption-enhanced colon-targeted delivery systems provide a feasible and innovative method to analyze the mechanism behinds the health benefits of foodborne biocompounds.

6-Gingerol is the major pungent component in ginger. It possesses a variety of health benefits including antitumor, anti-inflammatory and antioxidant, hypoglycemic, hypolipidemic and hypotensive activities as well as colitis prevention and treatment. However, the health effects of oral 6-gingerol are limited due to the low water solubility, poor gastrointestinal stability, rapid metabolism in the body, release at non-target sites, and pungent and bitter taste. In this article, the health effects of 6-gingerol including anticancer, anti-inflammatory and hypolipidemic activity, and preventing and treating cardiovascular and cerebrovascular diseases as well as gastrointestinal diseases are reviewed together with the underlying mechanisms. Based on a review of recent progress in the research on the gastrointestinal absorption of 6-gingerol, its distribution, metabolism and excretion in the systematic circulation and its metabolic processes in the upper and lower gastrointestinal tract, the current status of the design and development of oral delivery systems for 6-gingerol. The mechanism for the enhancing effect of delivery systems on the health benefits of 6-gingerol and the design principle of the strategies to enhance the health benefits of 6-gingerol are elucidated. Hopefully, this review will not only provide a theoretical guidance for the design of oral delivery systems for 6-gingerol and the research on the mechanism for the enhancing effect of oral delivery systems on the health benefits of 6-gingerol, but also provide scientific evidence for the design of 6-gingerol-based functional foods.

Lipid phase composition of nanostructured lipid carriers (NLCs) modulates their digestive release behavior and cellular uptake by macrophage. In this study, the effects of the percentage of beeswax in the binary lipid mixture on the physical properties, lipid digestion, curcumin release, intestinal adhesion and penetration, and macrophage uptake of NLCs were investigated by in vivo simulated digestion, ex vivo intestinal adhesion and penetration and RAW264.7 mouse macrophage uptake experiments. The results showed that the particle size, loading efficiency and encapsulation efficiency of NLCs increased with an increase in the percentage of beeswax in the lipid phase. Compared with NLCs without beeswax (NLC0), whose oil phase consisted of medium chain fatty acid triglycerides (MCT), addition of 5% or 10% beeswax to MCT significantly improved the apparent viscosity, physical stability, intestinal mucosal adhesion and penetration of NLCs (the fluorescence signal intensity of curcumin in epithelial cells increased by 20.27% and 55.02%, respectively). Additionally, with an increase in beeswax content, the lipolysis efficiency, the release rate of free fatty acid (FFA) and the amount of released curcumin from NLCs decreased significantly; the release rate of FFA decreased in the following order: K_NLC0 (0.13 min^-1) > K_NLC5 (0.08 min^-1) > K_NLC10 (0.06 min^-1), and the amount of released curcumin declined in the following order: R_NLC0 ((99.93 ± 0.09)%) > R_NLC5 ((96.38 ± 0.05)%) > R_NLC10 ((90.05 ± 0.05)%), indicating sustained release characteristics. Compared with free curcumin, NLCs promoted the enrichment of curcumin in RAW264.7 macrophages by 5.68–6.25 times. These findings can provide guidance for the application of beeswax based NLCs in oral delivery of lipophilic active ingredients and regulation of health effects.

Gel beads, as a novel type of functional food carrier, have shown promising potential for the encapsulation, enhanced stability and gastrointestinal delivery of bioactive compounds. The unique three-dimensional network structure of gel beads effectively protects bioactive compounds (e.g., essential oils, polysaccharides, polyphenols, and flavonoids) from environmental degradation while enabling their controlled release in the digestive system, thereby significantly improving their bioavailability. This review summarizes recent advances in the preparation, material development, and functional application of gel beads, focusing on their advantages in encapsulating flavor and active ingredients, stabilizing compounds, and enabling targeted delivery and controlled release in the digestive tract. Furthermore, future prospects for the application of gel beads for encapsulating and stabilizing omega-3 fatty acids and probiotics are discussed, thereby providing theoretical insights and technical guidance for the design of functional gel bead delivery systems and the stabilization of bioactive ingredients.