Development of Organogel-Derived Capsaicin Nanoemulsion with Improved Bioaccessibility and Reduced Gastric Mucosa Irritation

Controlling release of astaxanthin in β-sitosterol oleogel-based emulsions via different self-assembled mechanisms and composition of the oleogelators

In this study, three types of β-sitosterol-based oleogels (β-sitosterol + γ-oryzanol oleogels, β-sitosterol + lecithin, oleogels and β-sitosterol + monostearate oleogels), loaded with astaxanthin, were employed as the oil phase to create oleogel-based emulsions (SO, SL, and SM) using high-pressure homogenization. The microstructure revealed that fine-scale crystals were dispersed within the oil phase of the droplets in the β-sitosterol oleogel-based emulsion. The bioaccessibility of astaxanthin was found to be 58.13 %, 51.24 %, 36.57 %, and 45.72 % for SM, SL, SO, and the control group, respectively. Interestingly, the release of fatty acids was positively correlated with the availability of astaxanthin (P = 0.981). Further analysis of FFAs release and kinetics indicated that the structural strength of the oil-phase in the emulsions influenced the degree and rate of lipolysis. Additionally, the micellar fraction analysis suggested that the nature and composition of the oleogelators in SM and SL also impacted lipolysis and the bioaccessibility of astaxanthin. Furthermore, interfacial binding of lipase and isothermal titration calorimetry (ITC) measurements revealed that the oleogel network within the oil phase of the emulsion acted as a physical barrier, hindering the interaction between lipase and lipid. Overall, β-sitosterol oleogel-based emulsions offer a versatile platform for delivering hydrophobic molecules, enhancing the bioavailability of active compounds, and achieving sustained release.

Organogels: "GelVolution" in Topical Drug Delivery - Present and Beyond

Topical drug delivery holds immense significance in dermatological treatments due to its non-invasive nature and direct application to the target site. Organogels, a promising class of topical drug delivery systems, have acquired substantial attention for enhancing drug delivery efficiency. This review article aims to explore the advantages of organogels, including enhanced drug solubility, controlled release, improved skin penetration, non-greasy formulations, and ease of application. The mechanism of organogel permeation into the skin is discussed, along with formulation strategies, which encompass the selection of gelling agents, cogelling agents, and additives while considering the influence of temperature and pH on gel formation. Various types of organogelators and organogels and their properties, such as viscoelasticity, non-birefringence, thermal stability, and optical clarity, are presented. Moreover, the biomedical applications of organogels in targeting skin cancer, anti-inflammatory drug delivery, and antifungal drug delivery are discussed. Characterization parameters, biocompatibility, safety considerations, and future directions in optimizing skin permeation, ensuring long-term stability, addressing regulatory challenges, and exploring potential combination therapies are thoroughly examined. Overall, this review highlights the immense potential of organogels in redefining topical drug delivery and their significant impact on the field of dermatological treatments, thus paving the way for exciting prospects in the domain.

Lactobacillus reuteri CCFM1175 and Lactobacillus paracasei CCFM1176 Could Prevent Capsaicin-Induced Ileal and Colonic Injuries

Capsaicin (CAP) is usually reported to have many biological activities. However, a large intake of CAP may cause heartburn, gastrointestinal pain, and diarrhea. In this study, mice were gavaged with nine lactic acid bacteria (LAB) strains for two weeks, in which the mice were treated with CAP at the second week and lasted for one week. We tried to identify potential probiotics that could prevent CAP-induced intestinal injury and investigate the mechanisms. The modulation of transient receptor potential vanilloid 1 (TRPV1), levels of short-chain fatty acids (SCFAs), and the composition of gut microbiota were analyzed. The results showed that Lactobacillus reuteri CCFM1175 and Lactobacillus paracasei CCFM1176 effectively attenuated CAP-induced injuries to the ileum and colon, including relieving the damage to colonic crypt structures, increasing the number of goblet cells, decreasing levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), increasing levels of anti-inflammatory factors (IL-10), and reducing levels of substance P (SP) and calcitonin gene-related peptide (CGRP) in serum and colon tissue. Further analysis showed that L. reuteri CCFM1175 increased the relative abundance of Ruminococcaceae UCG_014 and Akkermansia. L. paracasei CCFM1176 downregulated the expression of TRPV1 in the ileal and colonic tissues and promoted the relative abundance of Ruminococcaceae UCG_014 and Lachnospiraceae UCG_006. These results indicate that L. reuteri CCFM1175 and L. paracasei CCFM1176 could prevent CAP-induced intestinal injury and be used as probiotics to improve the gastrointestinal health.

Sucrose Esters as Oleogelators in Mono or Binary Structured Oleogels Using Different Oleogelation Routes

Sucrose esters (SE) have been investigated as structuring agents in oleogels. Due to the low structuration power of SE as single agent, this component has recently been explored in combination with other oleogelators to form multicomponent systems. This study aimed to evaluate binary blends of SEs with different hydrophilic-lipophilic balances (HLBs) with lecithin (LE), monoglycerides (MGs) and hard-fat (HF), according to their physical properties. The following SEs, SP10-HLB2, SP30-HLB6, SP50-HLB11, and SP70-HLB15, were structured using three different routes: "traditional", "ethanol" and "foam-template". All binary blends were made using a 10% oleogelator in 1:1 proportion for binary mixtures; they were then evaluated for their microstructure, melting behavior, mechanical properties, polymorphism and oil-binding capacity. SP10 and SP30 did not form well-structure and self-standing oleogels in any combination. Although SP50 showed some potential blends with HF and MG, their combination with SP70 led to even more well-structured oleogels, with a higher hardness (~0.8 N) and viscoelasticity (160 kPa), and 100% oil-binding capacity. This positive result might be attributed to the reinforcement of the H-bond between the foam and the oil by MG and HF.

Capsaicin encapsulated in W/O/W double emulsions fabricated via ethanol-induced pectin gelling: Improvement of bioaccessibility and reduction of irritation

Capsaicin is a water-insoluble bioactive component with several beneficial physiological functions. However, the widespread application of this hydrophobic phytochemical is limited by its low water-solubility, intense irritation, and poor bioaccessibility. These challenges can be overcome by entrapping capsaicin within the internal water phase of water-in-oil-in-water (W/O/W) double emulsions via using ethanol to induce pectin gelling. In this study, ethanol was used both to dissolve capsaicin and to promote pectin gelation, thereby forming capsaicin-loaded pectin hydrogels that were used as the internal water phase of the double emulsions. Pectin addition improved the physical stability of the emulsions and led to a high encapsulation efficiency of capsaicin (>70 % after 7d storage). After simulated oral and gastric digestion, capsaicin-loaded double emulsions maintained their compartmentalized structure, avoiding capsaicin leakage in the month and stomach. The double emulsions were digested in the small intestine, thereby releasing the capsaicin. Capsaicin bioaccessibility was significantly enhanced after encapsulation, which was attributed to mixed micelle formation by the digested lipid phase. Furthermore, encapsulation of capsaicin within the double emulsions reduced the irritation in the gastrointestinal tissues of mice. This kind of double emulsion may have great potential for the development of more palatable capsaicin-loaded functional food products.

Capsaicin ameliorates diet-induced disturbances of glucose homeostasis and gut microbiota in mice associated with the circadian clock

Glucose metabolism disorder triggered by a high-energy diet is associated with circadian disruption in the brain, peripheral tissues and gut microbiota. The present study aims to investigate the regulating effects of capsaicin (CAP) on the diet-induced disturbances of glucose homeostasis and gut microbiota in respect of circadian rhythm-related mechanisms. Our results indicated that CAP significantly ameliorated glucose metabolism disorder in mice induced by a high-fat and high-fructose diet (HFFD). The rhythmic expressions of circadian clock genes (Bmal1, Clock, and others) and glucose metabolism-related genes (Pgc-1α, Glut2, G6pc, and Pepck) in the liver disrupted by an abnormal diet were also recovered by CAP. Microbial studies using 16S rDNA sequencing revealed that CAP modulated the structure and composition of gut microbiota and improved the circadian oscillations of Firmicutes and Bacteroidetes at the phylum level and Allobaculum, Bacteroides, Bifidobacterium, and Alistipes at the genus level. Correlation analysis indicated that a close correlation existed between intestinal microbiota, hepatic circadian gene expressions and the level of glucose metabolism-related factors, indicating that CAP could alleviate HFFD-induced disturbances of glucose metabolism and gut microbiota associated with circadian clock related mechanisms.

Digestion behaviour of capsaicinoid-loaded emulsion gels and bioaccessibility of capsaicinoids: Effect of emulsifier type

In this study, the effect of emulsifier type, i.e. whey protein versus Tween 80, on the digestion behaviour of emulsion gels containing capsaicinoids (CAPs) was examined. The results indicate that the CAP-loaded Tween 80 emulsion gel was emptied out significantly faster during gastric digestion than the CAP-loaded whey protein emulsion gel. The Tween-80-coated oil droplets appeared to be in a flocculated state in the emulsion gel, had no interactions with the protein matrix and were easily released from the protein matrix during gastric digestion. The whey-protein-coated oil droplets showed strong interactions with the protein matrix, and the presence of thick protein layer around the oil droplets protected their liberation during gastric digestion. During intestinal digestion, the CAP-loaded Tween 80 emulsion gel had a lower extent of lipolysis than the CAP-loaded whey protein emulsion gel, probably because the interfacial layer formed by Tween 80 was resistance to displacement by bile salts, and/or because Tween 80 formed interfacial complexes with bile salts/lipolytic enzymes. Because of the softer structure of the CAP-loaded Tween 80 emulsion gel, the gel particles were broken down much faster and the oil droplets were liberated from the protein matrix more readily than for the CAP-loaded whey protein emulsion gel during intestinal digestion; this promoted the release of CAP molecules from the gel. In addition, the Tween 80 molecules displaced from the interface would participate in the formation of mixed micelles and would help to solubilize the released CAP molecules, leading to improved bioaccessibility of CAP. Information obtained from this study could be useful in designing functional foods for the delivery of lipophilic bioactive compounds.

Association between chili pepper consumption and risk of gastrointestinal-tract cancers: A meta-analysis

Background

Stimulating food is emerging as an important modifiable factor in the development of gastrointestinal (GI) tract cancers, but the association between chili pepper consumption and the risk of GI cancers is unclear. We aimed to evaluate the direction and magnitude of the association between chili pepper consumption and the risk of GI cancers.

Methods

A literature search was performed in PubMed, Embase, and Web of Science databases from inception to 22 December 2021. Observational studies reporting the association between chili pepper consumption and the risk of gastric cancer (GC), esophageal cancer (EC), and/or colorectal cancer (CRC) in adults were eligible for inclusion. Data extraction and quality assessment were conducted independently by two reviewers for the included literature. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup analyses were also performed based on the cancer type, study design, region of the study, study quality, and adjustments.

Results

A total of 11,421 studies were screened, and 14 case-control studies were included involving 5009 GI cancers among 11,310 participants. The summary OR showed that high consumption of chili pepper was positively related to the risk of GI cancers (OR = 1.64; 95% CI: 1.00–2.70). A stronger positive relationship was observed between chili pepper consumption and EC risk (OR = 2.71; 95% CI: 1.54–4.75), but there was no statistically significant association between GC and CRC risk. In analyses stratified by geographical location, a positive association was found between chili pepper consumption and the risk of GI cancers in Asian studies (OR = 2.50; 95% CI: 1.23–5.08), African studies (OR = 1.62; 95% CI: 1.04–2.52), and North American studies (OR = 2.61; 95% CI: 1.34–5.08), but an inverse association was seen in South American studies (OR = 0.50; 95% CI: 0.29–0.87) and European studies (OR = 0.30; 95% CI: 0.15–0.61).

Conclusion

This meta-analysis suggests that chili pepper is a risk factor for certain GI cancers (e.g., EC). Geographical regions influence the risk of GI cancers, especially in Asian, African, and North American populations, which require more attention during dietary guidance.

Systematic review registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022320670].

Fibrous and Spherical Aggregates of Ovotransferrin as Stabilizers for Oleogel-Based Pickering Emulsions: Preparation, Characteristics and Curcumin Delivery

This study aimed to explore the effects and mechanisms of differently shaped aggregates of ovotransferrin (OVT) particles on oleogel-based Pickering emulsions (OPEs). Medium-chain triglyceride oil-based oleogels were constructed using beeswax, and their gel-sol melting temperatures were investigated. Atomic force microscopy confirmed that both OVT fibrils and OVT spheres were successfully prepared, and the three-phase contact angle measurements indicated that fibrous and spherical aggregates of OVT particles possessed great potential to stabilize the OPEs. Afterward, the oil-in-water OPEs were fabricated using oleogel as the oil phase and OVT fibrils/spheres as the emulsifiers. The results revealed that OPEs stabilized with OVT fibrils (FIB-OPEs) presented a higher degree of emulsification, smaller droplet size, better physical stability and stronger apparent viscosity compared with OPEs stabilized with OVT spheres (SPH-OPEs). The freeze–thaw stability test showed that the FIB-OPEs remained stable after three freeze–thaw cycles, while the SPH-OPEs could barely withstand one freeze–thaw cycle. An in vitro digestion study suggested that OVT fibrils conferred distinctly higher lipolysis (46.0%) and bioaccessibility (62.8%) of curcumin to OPEs.

Zein/pullulan complex colloidal particle-stabilized Pickering emulsions for oral delivery of polymethoxylated flavones: protection effect and in vitro digestion

BACKGROUND

Polymethoxylated flavones (PMFs) show multiple biological functions, while their high hydrophobicity leads to a low bioaccessibility and limits their wide applications. The design of a reasonable food-grade drug delivery system is an effective strategy to improve the low bioaccessibility of PMFs. In this study, sinensetin, tangeretin and nobiletin were encapsulated in Pickering emulsions stabilized by zein/pullulan complex colloidal particles (ZPPs), and the protection effect and in vitro digestion were characterized.

RESULTS

Rheological analysis revealed that ZPP-Pickering emulsion loading with PMFs maintained a strong gel-like network structure. Moreover, the ability to scavenge free radicals of PMFs was improved by the emulsion delivery system. The antioxidant activity of PMFs encapsulated in Pickering emulsion was positively correlated with the oil volume fraction (φ). ZPP-Pickering emulsion loading with PMFs can effectively delay lipid oxidation, and the φ (70%) of Pickering emulsion showed the most pronounced effects, in which the lipid hydroperoxide content and malondialdehyde content decreased by 64.3% and 38.3% after 15 days of storage, compared with the bulk oil group, respectively. The bioaccessibility of the three PMFs has been increased by ZPP-Pickering emulsion simultaneously and it presented the highest values as its φ was 50%, in which the bioaccessibility of sinensetin, tangeretin and nobiletin increased by 2.5, 3.2 and 3.9 times, compared with the bulk oil group, respectively.

CONCLUSION

Pickering emulsion stabilized by ZPPs is an excellent nutrient delivery system for delivering three PMFs simultaneously and imparting functional properties to bioactive delivery systems. © 2022 Society of Chemical Industry.

Updated design strategies for oral delivery systems: maximized bioefficacy of dietary bioactive compounds achieved by inducing proper digestive fate and sensory attributes

Interest in the application of dietary bioactive compounds (DBC) in healthcare and pharmaceutical industries has motivated researchers to develop functional delivery systems (FDS) aiming to maximize their bioefficacy. As the direct and indirect health benefiting effects of DBC are acknowledged, traditional design principle of FDS aiming at improving the bioavailability of intact DBC is challenged by the updated one, where the maximized bioefficacy of DBC delivered by FDS will be achieved via rationally absorbed at target sites with proper metabolism pathways. This article briefly summarized the absorption and metabolic fates of orally digested DBC along with their direct and indirect mechanisms to perform health benefiting effects. Current strategies in designing the next generation FDS with an emphasis on their modulation effects on the distribution portion between the upper and lower digestive tract, portal vein and lymphatic absorption, human digestive and gut microbiota enzymatic mediated metabolism were highlighted. Updated research progresses of FDS in adjusting sensory attributes of food end products and inducing synergistic effects rooting from matrix materials and co-delivered cargos were also discussed. Challenges as well as future perspectives concerning the precise nutrition and the critical role of delivery systems in dietary intervention were proposed.

Emerging trends in nano-bioactive-mediated mitochondria-targeted therapeutic stratagems using polysaccharides, proteins and lipidic carriers

The emergence of new lifestyle disorders and pharmaco-resistant variants of diseases has necessitated the search for effective therapeutic moieties and approaches that could overcome the limitations in the existing treatment modalities. In this context, bioactives such as flavonoids, polyphenols, tannins, terpenoids and alkaloids have demonstrated promise in therapy owing to their ability to scavenge free radicals and modulate the mitochondrial function as well as regulate metabolic pathways. However, their clinical applicability is low owing to their poor bioavailability and aqueous solubility. The encapsulation of bioactives in nanodimensional particles has overcome these limitations to a large extent while simultaneously conferring additional advantages of improved circulation time, enhanced cell uptake and target specific release. A wide range of nanocarriers derived from biopolymers such as polysaccharides, lipids and proteins, have been explored for encapsulation of different bioactives and have reported significant improvement of the bioavailability and therapeutic efficacy of the encapsulated cargo. However, incorporation of cell-specific and mitochondria-specific elements on the nanocarriers has been relatively less explored. This review summarizes some of the recent attempts to treat different disorders using bioactives encapsulated in biopolymer nanostructures and few instances of mitochondria-specific delivery.

Capsaicin, the Spicy Ingredient of Chili Peppers: Effects on Gastrointestinal Tract and Composition of Gut Microbiota at Various Dosages

Capsaicin (CAP) is an ingredient of peppers that has biological activities at low doses but causes gastrointestinal (GI) discomfort at high doses. However, the GI effects of high doses of CAP and the evaluation criteria to determine this remain unknown. To elucidate the dose-related effects of CAP on GI health, CAP was administered to mice at 40, 60, and 80 mg/kg doses. The results showed that 40 mg/kg CAP did not negatively affect GI tissues, while 60 and 80 mg/kg CAP damaged GI tissues and caused significant inflammation in the jejunum, ileum, and colon. The levels of serum substance P (SP) and calcitonin gene-related peptide (CGRP) were CAP-dose-dependent, and short-chain fatty acids (SCFAs) content significantly increased in the 80 mg/kg group. Correlation analysis revealed that the underlying mechanisms might be related to the regulation of gut microbiota, especially Bifidobacterium, Lactobacillus, Faecalibacterium, and Butyricimonas. These results suggest that oral administration of 60 and 80 mg/kg CAP in mice causes intestinal inflammation and high levels of serum neuropeptides and cecal SCFAs, which may be related to alterations in gut microbiota.

Applications of capsaicin in food industry: functionality, utilization and stabilization

As a bioactive component in Capsicum species, capsaicin is a compound of hot chili peppers which is known as the main substance responsible for the spiciness of these fruits. Besides its taste and physiological effects, it exhibits good antioxidant activity in food matrix and antimicrobial activity against foodborne pathogens and viruses. Considering its low stability and bioaccessibility, and also regarding its irritation, the entrapment methods of capsaicin are fully developed. To compensate the limitations of capsaicin, various encapsulation methods have been used so far, including coacervation, emulsion, spray chilling, and liposomal delivery. Capsaicin has been widely used as a flavoring and preservative agent in food formulations and even as an active compound in packaging film and functional foods. This review provides an overview of the techno-functional properties, stabilization procedures, and burgeoning usages of capsaicin in the latest studies of the food sector. So, it may introduce new windows for the application of this compound.

A novel promising delivery system for cuminaldehyde using gelled lipid nanoparticles: Characterization and anticancer, antioxidant, and antibacterial activities

This work aimed to develop a novel nanoencapsulation system for food colloidal formulations using gelled lipid nanoparticles (GLNs) to improve the functionality, stability, and bioactivity of cuminaldehyde as a highly volatile and poor hydrophilic food additive. Cuminaldehyde-loaded GLNs with diameters of 117-138 nm were fabricated through a hot emulsification process with monoglyceride (10 and 15 g/100 g lipid phase) as a lipid gelator at two concentrations of cuminaldehyde (500 and 1000 mg/L). All samples remained stable towards macroscopic phase separation and creaming during 28 days of storage at 4 °C, which could be related to the rigid structure of dispersed particles in the gelled state and retarding droplet movement. Moreover, all samples were stable to creaming after subjecting to the environmental changes including temperature (30, 60, and 90 °C for 30 min), ionic strength (100, 200, and 300 mM NaCl), and pH (3, 5, and 7). Measurement of apparent viscosity showed non-Newtonian shear thinning nature in all samples, which was more pronounced at higher concentrations of the gelator. Interestingly, higher cytotoxic effects of cuminaldehyde against human lung and colorectal cancer cells were observed after encapsulation within GLNs. However, weak toxicity was also found against normal peripheral blood mononuclearcells.On the other hand, the antioxidant activity and lipid oxidation stability were improved by increasing cuminaldehyde concentration, while it was reduced at higher monoglyceride concentration. All samples exhibited stronger antibacterial activity against Bacillus cereus than Eschershia coli. These findings suggest the significant potential benefits of GLNs as novel nanocarriers to enrich various food and beverage formulations with essential oils, flavors, and aromas.

Development of organogel-based emulsions to enhance the loading and bioaccessibility of 5-demethylnobiletin

5-Demethylnobiletin (5-DMN), identified in the aged citrus peels, has received increasing attentions due to its outstanding bioactivity among citrus polymethoxyflavones (PMFs). However, the poor water solubility and high crystallinity limit its oral bioavailability. Besides, the solubility of 5-DMN in the oil is very limited, which restricts its loading capacity in emulsions for bioavailability enhancement. In this study, an organogel formulation was developed to improve the solubility of 5-DMN in medium-chain triacylglycerols by 3.5 times higher without crystal formation during 5-day storage at room temperature. Increasing the gelator (i.e., sugar ester) concentration led to the increase of viscosity and a gel-like structure of the organogel. The ternary phase diagram of organogel-based emulsions was explored, and 40% organogel was selected as the oil phase for emulsion preparation. Increasing the concentration of Tween 80 from 0% to 6% decreased the droplet size and viscoelasticity of the emulsions. Two in vitro models, the pH-stat lipolysis model and TNO gastro-intestinal model (TIM-1), were applied to investigate the bioaccessibility of 5-DMN in different delivery systems. Compared with the conventional emulsion and oil suspension, the pH-stat lipolysis demonstrated that the organogel-based emulsion was the most efficient tool to enhance 5-DMN bioacccessibility. Moreover, TIM-1 digestive study indicated that 5-DMN bioaccessibility delivered by organogel-based emulsions was about 3.26-fold higher than that of oil suspension. Our results suggested that the organogel-based emulsion was an effective delivery route to enhance the loading and bioaccessibility of lipophilic compounds of high crystallinity.

A novel strategy to fabricate stable oil foams with sucrose ester surfactant

HYPOTHESIS

Can a mixture of sucrose ester surfactant in vegetable oil be aerated to yield stable oleofoams? Is foaming achievable from one-phase molecular solutions and/or two-phase crystal dispersions? Does cooling a foam after formation induce surfactant crystallisation and enhance foam stability?

EXPERIMENTS

Concentrating on extra virgin olive oil, we first study the effect of aeration temperature and surfactant concentration on foamability and foam stability of mixtures cooled from a one-phase oil solution. Based on this, we introduce a strategy to increase foam stability by rapidly cooling foam prepared at high temperature which induces surfactant crystallisation in situ. Differential scanning calorimetry, X-ray diffraction, infra-red spectroscopy, surface tension and rheology are used to elucidate the mechanisms.

FINDINGS

Unlike previous reports, both foamability and foam stability decrease upon decreasing the aeration temperature into the two-phase region containing surfactant crystals. At high temperature in the one-phase region, substantial foaming is achieved (over-run 170%) within minutes of whipping but foams ultimately collapse within a week. We show that surfactant molecules are surface-active at high temperature and that hydrogen bonds form between surfactant and oil molecules. Cooling these foams substantially increases foam stability due to both interfacial and bulk surfactant crystallisation. The generic nature of our findings is demonstrated for a range of vegetable oil foams with a maximum over-run of 330% and the absence of drainage, coalescence and disproportionation being achievable.

Oleogel-Based Systems for the Delivery of Bioactive Compounds in Foods

Oleogels are semi-solid materials containing a large fraction of liquid oil entrapped in a network of structuring molecules. In the food industry, these formulations can be used to mimic fats and to deliver bioactive compounds. In the last decade, there has been increasing interest in these structures, not only from a scientific point of view, i.e., studying new molecules, methodologies for gelification, and new structures, but also from a technological point of view, with researchers and companies exploring these structures as a way to overcome certain challenges and/or create new and innovative products. One of the exciting applications of oleogels is the delivery of functional molecules, where the incorporation of oil-soluble functional compounds can be explored not only at the macroscale but also at micro- and nanoscales, resulting in different release behaviors and also different applications. This review presents and discusses the most recent works on the development, production, characterization, and applications of oleogels and other oleogel-based systems to deliver functional molecules in foods.

Structured edible lipid-based particle systems for oral drug-delivery

Oral administration is the most popular and patient-compliant route for drug delivery, though it raises great challenges due to the involvement of the gastro-intestine (GI) system and the drug bioavailability. Drug bioavailability is directly related to its ability to dissolve, transport and/or absorb through the physiological environment. A great number of drugs are characterized with low water solubility due to their hydrophobic nature, thus limiting their oral bioavailability and clinical use. Therefore, new strategies aiming to provide a protective shell through the GI system and improve drug solubility and permeability in the intestine were developed to overcome this limitation. Lipid-based systems have been proposed as good candidates for such a task owing to their hydrophobic nature which allows high drug loading, drug micellization ability during intestinal digestion due to the lipid content, and the vehicle physical protective environment. The use of edible lipids with high biocompatibility paves the bench-to-bedside translation. Four main types of structured lipid-based drug delivery systems differing in the physical state of the lipid phase have been described in the literature, namely emulsions, solid lipid nanoparticles, nanostructured lipid carriers, and oleogel-based particles. The current review provides a comprehensive overview of the different structured edible lipid-based oral delivery systems investigated up to date and emphasizes the contribution of each system component to the delivery performance, and the oral delivery path of lipids.

Recent advances on food-grade oleogels: Fabrication, application and research trends

In order to improve the nutritional and quality characteristics of food, solid fats are widely used in food formulations. With the continuous improvement of consumers' awareness of health in recent years, substantial attempts have been carried out to find substitutes for solid fats to reduce saturated fatty acid content in foods. Oleogels have drawn increasing attention due to their attractive advantages such as easy fabrication, superior fatty acid composition and safe use in food products to satisfy consumers' demands for healthy products. This review provides the latest information on the diversified oleogel systems. The feasibility of oleogel and oleogel-based system as nutraceutical vehicles is elucidated. The type as well as concentration of oleogelators and the synergistic effect between two or more oleogelators are important factors affecting the properties of obtained oleogel. Oleogels used in nutraceutical delivery have been shown to offer increased loading amount, enhanced bioaccessibility and targeted or controlled release. These nutrients wrapped in oleogels may in turn affect the formation and properties of oleogels. Furthermore, the future perspectives of oleogels are discussed. The feasible research trends of food-grade oleogel include oleogel-based solid lipid particle, essential oil-in-oleogel system, delivery of probiotics, nutraceuticals co-delivery and microencapsulated oleogel.

Exploiting drug delivery systems for oral route in the peptic ulcer disease treatment

Peptic ulcer disease (PUD) is a common condition that is induced by acid and pepsin causing lesions in the mucosa of the duodenum and stomach. The pathogenesis of PUD is a many-sided scenario, which involves an imbalance between protective factors, such as prostaglandins, blood flow, and cell renewal, and aggressive ones, like alcohol abuse, smoking, Helicobacter pylori colonisation, and the use of non-steroidal anti-inflammatory drugs. The standard oral treatment is well established; however, several problems can decrease the success of this therapy, such as drug degradation in the gastric environment, low oral bioavailability, and lack of vectorisation to the target site. In this way, the use of strategies to improve the effectiveness of these conventional drugs becomes interesting. Currently, the use of drug delivery systems is being explored as an option to improve the drug therapy limitations, such as antimicrobial resistance, low bioavailability, molecule degradation in an acid environment, and low concentration of the drug at the site of action. This article provides a review of oral drug delivery systems looking for improving the treatment of PUD.

Effect of Gel Structure on the In Vitro Gastrointestinal Digestion Behaviour of Whey Protein Emulsion Gels and the Bioaccessibility of Capsaicinoids

This study investigated the effect of gel structure on the digestion of heat-set whey protein emulsion gels containing capsaicinoids (CAP), including the bioaccessibility of CAP. Upon heat treatment at 90 °C, whey protein emulsion gels containing CAP (10 wt% whey protein isolate, 20 wt% soybean oil, 0.02 wt% CAP) with different structures and gel mechanical strengths were formed by varying ionic strength. The hard gel (i.e., oil droplet size d_4,3 ~ 0.5 μm, 200 mM NaCl), with compact particulate gel structure, led to slower disintegration of the gel particles and slower hydrolysis of the whey proteins during gastric digestion compared with the soft gel (i.e., d_4,3 ~ 0.5 μm, 10 mM NaCl). The oil droplets started to coalesce after 60 min of gastric digestion in the soft gel, whereas minor oil droplet coalescence was observed for the hard gel at the end of the gastric digestion. In general, during intestinal digestion, the gastric digesta from the hard gel was disintegrated more slowly than that from the soft gel. A power-law fit between the bioaccessibility of CAP (Y) and the extent of lipid digestion (X) was established: Y = 49.2 × (X - 305.3)^0.104, with R² = 0.84. A greater extent of lipid digestion would lead to greater release of CAP from the food matrix; also, more lipolytic products would be produced and would participate in micelle formation, which would help to solubilize the released CAP and therefore result in their higher bioaccessibility.

Mechanistic elucidation of the oral pungency of capsaicin-related dietary components: Spatial structural insights

The mechanistic insights into the oral pungency of capsaicin-related dietary components have been elucidated from the spatial structural perspectives by establishing statistically significant and highly predictive three-dimensional quantitative structure-property relationship models. Our results visualized the possible favorable and unfavorable steric and electrostatic interactions with the pungent receptors with the assistance of pharmacophore models, and revealed the suitable electronegative/positive or bulky substitutions in the vanillyl group, amide moiety, linear alkyl chain and their adjacent structural area of capsaicin required for the desired pungency, which was not only complementary to the viewpoints proposed in our previous structure-pungency correlations, but also was applied to clearly clarify the pungent differences in compounds, and well predict the pungency of 21 capsaicin analogs though with ambiguous experimental data on pungency. Hopefully, this work would benefit the overall understanding of the pungent mechanism and facile discovery/design of analogs with desired pungency to expand their applications in foods.

Phenolics Dynamics and Infrared Fingerprints during the Storage of Pumpkin Seed Oil and Thereof Oleogel

Cold-pressed pumpkin seed oil is a valuable source of bioactive molecules, including phenolic compounds. Oleogels are designed for trans and saturated fats substitution in foods, but also demonstrate protection and delivery of bioactive compounds. Consequently, the present work aimed to assess individual phenolic compounds dynamics and infrared fingerprints during the ambient storage of pumpkin seed oil and thereof oleogel. For oleogels production, a 5% ternary mixture of waxes, composed by 3% beewax, 1% sunflower wax and 1% rice bran wax, was used. Phenolic compounds were extracted by traditional liquid–liquid extraction, followed by HPLC-MS quantification. FTIR (400–4000 cm−1) was used for characterizing and monitoring the oxidative stability of all samples and for the evaluation of intermolecular forces between oleogelator mixtures and oil. Specific wavenumbers indicated oxidative processes in stored sample sets; storage time and sample clustering patterns were revealed by chemometrics. Isolariciresinol, vanillin, caffeic and syringic acids were quantified. The main changes were determined for isolariciresinol, which decreased in liquid pumpkin seed oil samples from 0.77 (T1) to 0.13 mg/100 g (T4), while for oleogel samples it decreased from 0.64 (T1) to 0.12 mg/100 g (T4). However, during the storage at room temperature, it was concluded that oleogelation technique might show potential protection of specific phenolic compounds such as syringic acid and vanillin after 8 months of storage. For isolariciresinol, higher amounts are registered in the oleogel (0.411 mg/100 g oil) than in the oil (0.37 mg/100 g oil) after 5 months of ambient temperature storage (T3). Oxidation processes occurred after 5 months storage for both oil and oleogel samples.

Urea-Based Low-Molecular-Weight Pseudopeptidic Organogelators for the Encapsulation and Slow Release of (R)-Limonene

Low-molecular-weight compounds containing alkylurea fragments attached to the amino end of different miminalistic pseudopeptidic structures have been shown to be excellent organogelators in a variety of organic solvents and liquid organic compounds of different nature. The formation of gels in this work is defined through rheological measurements for those cases where G' > G''. Both the topology and the symmetry of the corresponding urea compounds play a role in defining their organogelator behavior. This can also be tuned by the presence of additional supramolecular guests, as is the case for suberic acid. These compounds also achieve the gelation of relevant active substances such as terpene natural oils and complex mixtures of flavors and fragrances. This provides a simple and mass-efficient supramolecular system for the quantitative encapsulation of active substances, without the need for any additional solvent or complex processes, and their consequent controlled release.

Supramolecular Organogelation Directed by Weak Noncovalent Interactions in Palmitoylated 1,5-Anhydro-d-Glucitol Derivatives

We synthesized a series of novel alicyclic compounds by modifying 1,5-anhydro-d-glucitol with two to four palmitoyl chains, and we explored their self-assembly and gelation behaviors in paraffin. The obtained organogels were studied by field emission scanning electron microscopy, atomic force microscopy, variable-temperature Fourier transform IR spectroscopy, X-ray diffraction analysis, polarized optical microscopy, and transmission spectroscopy. While all the palmitoylated derivatives spontaneously formed fibrous networks and gelated the paraffin, an acetylated derivative of 1,5-anhydro-d-glucitol did not gelatinize the solvent, thus indicating the importance of aliphatic chains for gelation. Interestingly, α- and β- d-glucopyranose with five palmitoyl chains neither gelatinized the solvent nor formed fibrous networks, thus suggesting that the absence of C-1 substitution in 1,5-anhydro-d-glucitol is important for gelation. Fourier transform IR spectroscopy suggested that the formation of weak hydrogen bonds between the carbonyl groups and the C-H groups was the driving force for formation of the supramolecular fibers and for gelation of the solvent.

Capsaicin—the major bioactive ingredient of chili peppers: bio-efficacy and delivery systems

The mechanisms of bio-efficacy of capsaicin and delivery systems with enhanced bioavailability were reviewed.

Anti-obesity effects of capsaicin and the underlying mechanisms: a review

The mechanisms of anti-obesity effects of capsaicin in cell models, rodent models and human subjects were reviewed.

Capsaicin Ameliorates the Redox Imbalance and Glucose Metabolism Disorder in an Insulin-Resistance Model via Circadian Clock-Related Mechanisms

Circadian rhythms are closely associated with metabolic homeostasis. Metabolic disorders can be alleviated by many bioactive components through controlling of clock gene expressions. Capsaicin has been demonstrated with many beneficial effects including anti-obesity and anti-insulin resistance activities, yet whether the rhythmic expression of circadian clock genes are involved in the regulation of redox imbalance and glucose metabolism disorder by capsaicin remains unclear. In this work, the insulin resistance was induced in HepG2 cells by treatment of glucosamine. Glucose uptake levels, reactive oxygen species, H₂O₂ production, and mitochondrial membrane potential (MMP) were measured with/without capsaicin cotreatment. The mRNA and protein expressions of core circadian clock genes were evaluated by RT-qPCR and western blot analysis. Our study revealed that circadian misalignment could be ameliorated by capsaicin. The glucosamine-induced cellular redox imbalance and glucose metabolism disorder were ameliorated by capsaicin in a Bmal1-dependent manner.

Nanoencapsulation of functional food ingredients

Many functional food ingredients are poorly soluble in water, susceptible to chemical degradation, and incompatible with surrounding food matrix. Other issues are related to limited oral bioavailability, unpleasant sensory properties, and poor release profiles. Nanoencapsulation of functional food ingredients can help increase their water solubility/dispersibility in foods and beverages, improve their bioavailability by exhibiting good dose-dependent functionalities, mask undesired flavors/tastes to reduce the adverse effect on mouth-feel, enhance shelf-life and compatibility during production, storage, transportation and utilization of food products, and control release rate or specific delivery environment for better performance on their functionalities. This chapter provides an overview of different delivery systems for different functional food ingredients, the types of materials suitable for wall materials or building blocks of nanocapsules, the fabrication methods to assemble different delivery systems and release these active ingredients under different physiological conditions.

Design of gel structures in water and oil phases for improved delivery of bioactive food ingredients

Gels are viscoelastic systems built up with a liquid phase entrapped in a three-dimensional network, which can behave as carriers for bioactive food ingredients. Many attempts have been made to design gel structures in the water phase (hydrogels, emulsion gels, bigels) or oil phase (organogels, bigels) in order to improve their delivery performances. Hydrogels are originated from proteins or polysaccharides, which are suitable for the delivery of hydrophilic ingredients. Organogels are mainly built up with the self-assembling of gelator molecules in the oil phase, and they offer good carriers for lipophilic ingredients. Emulsion gels and bigels, containing both aqueous and oil domains, can provide accommodations for lipophilic and hydrophilic ingredients simultaneously. Gel structures (e.g. rheology, texture, water holding capacity, swelling ratio) can be modulated by choosing different gelators, modifying gelation techniques, and the involvement of other ingredients (e.g. oils, emulsifiers, minerals, acids), which then alter the diffusion and release of the bioactive ingredients incorporated. Various studies have proved that gel-based delivery systems are able to improve the stability and bioavailability of many bioactive food ingredients. This review provides a state-to-art overview of different gel-based delivery systems, highlighting the significance of structure-functionality relationship, to provide advanced knowledge for the design of novel functional foods.