Encapsulation of curcumin within oil-in-water emulsions prepared by premix membrane emulsification: Impact of droplet size and carrier oil type on physicochemical stability and in vitro bioaccessibility

Enhancing curcumin stability and bioavailability through chickpea protein isolate-citrus pectin conjugate emulsions: Targeted delivery and gut microecology modulation

The limited solubility, rapid metabolism, and poor bioavailability of curcumin restrict its application. In this study, we synthesized chickpea protein isolate (CPI)-citrus pectin (CP) conjugates to prepare an emulsion delivery system that enhances the stability and bioavailability of curcumin. The CPI-CP emulsion achieved a curcumin encapsulation efficiency of 86.15 %. Additionally, the stability of curcumin within CPI-CP emulsion was enhanced under conditions of thermal, UV irradiation, and oxidation. In vitro digestion demonstrated that the CPI-CP conjugates effectively preserved the interfacial film integrity during gastric digestion, facilitating targeted delivery of curcumin to the small intestine. This resulted in a substantial increase in curcumin bioavailability, from 50.60 % to 85.60 %. In vivo, the emulsion alleviated liver oxidative stress by improving antioxidant enzyme activity and promoted gut health through increased short-chain fatty acid production and modulation of gut microbiota. This research presents an effective strategy for enhancing the stability and bioavailability of curcumin and demonstrates the potential application of CPI-CP conjugates in delivery systems for bioactive substances.

Improved solubility and bioavailability of cyclolinopeptides by diacylglycerol in the β-cyclodextrin Pickering emulsions

Cyclolinopeptides (CLs) have anti-inflammatory, anti-osteoporosis, and anti-tumor effects, however, low water and oil solubility greatly limit their application. Herein, CLs-loaded β-cyclodextrin (β-CD) emulsions were prepared with different oil phases. The in vitro digestibility, cellular absorption, and anti-inflammatory effects were evaluated. Camellia oil diacylglycerol (CO DAG) showed enhanced dissolving ability for CLs due to high polarity. β-CD formed inclusion complexes with DAG through hydrogen bond and the emulsions showed smaller size and higher physical stability with 50 % (w/w) oil. The in vitro digestibility of the DAG emulsion was increased and the CLs' bioavailability was 13.6-fold higher than CLs in oil. The CLs-loaded Pickering emulsion digesta exhibited a higher nitric oxides (NO) inhibition rate (58.62 %) and Caco-2 cell penetration (3.09 × 10-6 cm/s). Therefore, emulsion formulated with β-cyclodextrin and DAG can effectively improve the solubility and bioavailability of CLs, which has significant potential for application in functional foods and pharmaceutical industry.

Recent advances in the development and application of curcumin-loaded micro/nanocarriers in food research

The application of curcumin in food science is challenged by its poor water solubility, easy degradation under processing and within the gastrointestinal tract, and poor bioavailability. Micro/nanocarrier is an emerging and efficient platform to overcome these drawbacks. This review focuses on the recent advances in the development and application of curcumin-loaded micro/nanocarriers in food research. The recent development advances of curcumin-loaded micro/nanocarriers could be classified into ten basic systems: emulsions, micelles, dendrimers, hydrogel polymeric particles, polymer nanofibers, polymer inclusion complexes, liposomes, solid lipid particles, structured lipid carriers, and extracellular vesicles. The application advances of curcumin-loaded micro/nanocarriers for food research could be classified into four types: coloring agents, functional active agents, preservation agents, and quality sensors. This review demonstrated that micro/nanocarriers were excellent carriers for the fat-soluble curcumin and the obtained curcumin-loaded micro/nanocarriers had promising application prospects in the field of food science.

Unlocking curcumin's revolutionary: Improvement of stability and elderly digestion by soybean oil bodies and soybean protein-chitosan complex based Pickering emulsion

Curcumin shows promise for disease prevention and health improvement, but its limited water solubility and vulnerability to degradation reduce its bioavailability, while its biological fate in elderly is unclear. Oil bodies are natural pre-emulsified oil droplets that serve as carriers for functional nutrients. In this study, soybean protein isolate (SPI) was complexed with chitosan (CS) for the purpose of stabilizing the soybean oil body-curcumin emulsion, resulting in the formation of the soybean isolate protein-chitosan-soybean oil bodies-curcumin Pickering emulsion (SPI-CS-SOB-C). The study examined the digestive properties, bioaccessibility of curcumin, free fatty acids (FFA) release, and microstructure changes of SPI-CS-SOB-C through an in vitro elderly digestion model. The findings indicated that curcumin was effectively encapsulated within the SPI-CS-SOB-C, achieving an encapsulation efficiency of 97.7 %, which resulted in notable enhancements in light, heat, and storage stability, as well as an extended half-life of curcumin to 85 months. In vitro elderly digestion demonstrated that SPI-CS-SOB-C notably enhanced the bioaccessibility of curcumin, increasing it from 14.3 % to 51 %. The low FFA release of SPI-CS-SOB-C (23.06 %) suggested its potential suitability for incorporation into low-fat food products and using in food products for the elderly. The results of this study could offer theoretical insights for the utilization of oil bodies in food applications and the delivery of functional nutrients.

Curcumin-encapsulated glucan nanoparticles as an oxidative stress modulator against human hepatic cancer cells

In Hepatitis B patients, the virus targets liver cells, leading to inflammation and liver damage, which can result in severe complications such as liver failure, cirrhosis, and liver cancer. Therapeutic options for liver disease are currently limited. Curcumin, a polyphenol with potential protective effects against chronic diseases like cancer, suffers from poor water solubility, restricting its pharmacological applications. This study explores the encapsulation of curcumin in glucan nanoparticles (NPs) and its impact on oxidative stress in liver cancer cells. Two sizes of curcumin-loaded glucan NPs, GC111 (111 nm) and GC398 (398 nm), were produced with nearly 100 % encapsulation efficiency. Cytotoxicity studies revealed that particle size influences the extent of observed effects, with GC111 NPs causing a greater reduction in cell viability. Additionally, the smaller GC111 NPs demonstrated a higher capacity to induce oxidative stress in cancer cells by stimulating the production of ROS, NO, and the chemokine RANTES in a concentration-dependent manner. These findings suggest that the smaller GC111 NPs are promising candidates for future studies aimed at evaluating oxidative stress-induced tumor cell death mechanisms.

Impact of κ-Carrageenan on the Freshwater Mussel (Solenaia oleivora) Protein Emulsion Gels: Gel Formation, Stability, and Curcumin Delivery

Protein-based emulsion gels are an ideal delivery system due to their unique structure, remarkable encapsulation efficiency, and tunable digestive behavior. Freshwater mussel (Solenaia oleivora) protein isolate (SoPI), an emerging sustainable protein with high nutritional value, possesses unique value in the development of functional foods. Herein, composite emulsion gels were fabricated with SoPI and κ-carrageenan (κ-CG) for the delivery of curcumin. SoPI/κ-CG stabilized emulsions possessed a high encapsulation efficiency of curcumin with a value of around 95%. The addition of κ-CG above 0.50% facilitated the emulsion gel formation and significantly improved the gel strength with 1326 g. Furthermore, the storage and digestive stability of curcumin were significantly improved as the κ-CG concentration increased. At 1.50% κ-CG, around 80% and 90% curcumin remained after 21-day storage at 45 °C and the 6 h in vitro gastrointestinal digestion, respectively. The addition of 0.50% κ-CG obtained the highest bioaccessibility of curcumin (~60%). This study illustrated the potential of SoPI emulsion gels as a carrier for stabilizing and delivering hydrophobic polyphenols.

Interactions of White Mugwort (Artemisia lactiflora Wall.) Extract with Food Ingredients during In Vitro Gastrointestinal Digestion and Their Impact on Bioaccessibility of Polyphenols in Various Model Systems

The bioaccessibility of phytochemicals is an important factor for new functional food design. The interaction of white mugwort extract (FE) and food ingredients (coconut oil, egg white albumen, brown rice powder, inulin, and mixtures thereof) was determined after in vitro digestion to inform the development of a functional soup for an aging population. Coconut oil exerted a protective effect on polyphenols, showing the highest bioaccessibility (62.9%) and antioxidant activity after intestinal digestion (DPPH 12.38 mg GAE/g DW, FRAP 0.88 mol Fe(ll)/g DW). In contrast, egg white albumen had the most significant negative effect on the polyphenol stability, resulting in the lowest bioaccessibility (12.49%). Moreover, FE promoted the emulsion stability and delayed starch digestion by inhibiting amylase activity via non-specific polyphenol-protein interactions, resulting in a decrease in the total reducing sugars (TRS) released during digestion. It also limited the protein digestion, probably due to the complex formation of polyphenols and proteins, consequently reducing the bioaccessibility of both amino acids and polyphenols. These findings provide useful information for designing functional food products that could promote the bioaccessibility and bioactivity of natural extracts.

Probabilistic Modelling of the Food Matrix Effects on Curcuminoid's In Vitro Oral Bioaccessibility

The bioaccessibility of bioactive compounds plays a major role in the nutritional value of foods, but there is a lack of systematic studies assessing the effect of the food matrix on bioaccessibility. Curcuminoids are phytochemicals extracted from Curcuma longa that have captured public attention due to claimed health benefits. The aim of this study is to develop a mathematical model to predict curcuminoid's bioaccessibility in biscuits and custard based on different fibre type formulations. Bioaccessibilities for curcumin-enriched custards and biscuits were obtained through in vitro digestion, and physicochemical food properties were characterised. A strong correlation between macronutrient concentration and bioaccessibility was observed (p = 0.89) and chosen as a main explanatory variable in a Bayesian hierarchical linear regression model. Additionally, the patterns of food matrix effects on bioaccessibility were not the same in custards as in biscuits; for example, the hemicellulose content had a moderately strong positive correlation to bioaccessibility in biscuits (p = 0.66) which was non-significant in custards (p = 0.12). Using a Bayesian hierarchical approach to model these interactions resulted in an optimisation performance of r2 = 0.97 and a leave-one-out cross-validation score (LOOCV) of r2 = 0.93. This decision-support system could assist the food industry in optimising the formulation of novel food products and enable consumers to make more informed choices.

Films Based on Biopolymers Incorporated with Active Compounds Encapsulated in Emulsions: Properties and Potential Applications-A Review

The rising consumer demand for safer, healthier, and fresher-like food has led to the emergence of new concepts in food packaging. In addition, the growing concern about environmental issues has increased the search for materials derived from non-petroleum sources and biodegradable options. Thus, active films based on biopolymers loaded with natural active compounds have great potential to be used as food packaging. However, several lipophilic active compounds are difficult to incorporate into aqueous film-forming solutions based on polysaccharides or proteins, and the hydrophilic active compounds require protection against oxidation. One way to incorporate these active compounds into film matrices is to encapsulate them in emulsions, such as microemulsions, nanoemulsions, Pickering emulsions, or double emulsions. However, emulsion characteristics can influence the properties of active films, such as mechanical, barrier, and optical properties. This review addresses the advantages of using emulsions to encapsulate active compounds before their incorporation into biopolymeric matrices, the main characteristics of these emulsions (emulsion type, droplet size, and emulsifier nature), and their influence on active film properties. Furthermore, we review the recent applications of the emulsion-charged active films in food systems.

Influence of 1,3-diacylglycerol on physicochemical and digestion properties of nanoemulsions and its enhancement of encapsulation and bioaccessibility of hydrophobic nobiletin

Lipid-based delivery systems are commonly used to encapsulate hydrophobic bioactive compounds for enhancing their bioaccessibility and bioavailability, especially for triacylglycerol (TAG) oil-based delivery systems. However, studies on the development of 1,3-diacylglycerol (DAG) oil-based delivery systems are rather limited. Herein, the influence of 1,3-DAG oil as a carrier oil on the properties of nanoemulsions and the bioaccessibility of encapsulated hydrophobic nobiletin (NOB) were investigated. High-purity 1,3-DAG (over 93% pure) was prepared by a combination of enzymatic esterification and ethanol crystallization. 1,3-DAG oil as a carrier oil could be used to formulate nanoemulsions with smaller droplet size, narrower size distribution and similar stability compared to TAG oil. Importantly, 1,3-DAG oil could efficiently encapsulate high-loading NOB (1.45 mg g-1) in nanoemulsions and significantly improve the bioaccessibility of NOB (above 80%), which is attributable to its massive lipolysis and higher encapsulation capacity than TAG oil. Moreover, the addition of the 1,3-DAG component in TAG oil significantly improved the properties of nanoemulsions and the loading and bioaccessibility of NOB, especially as the 1,3-DAG content was not less than 50%. The structure of lipids (DAG versus TAG) influenced the nanoemulsion properties and the bioaccessibility of encapsulated NOB. Based on the good properties of 1,3-DAG oil coupled with its health benefits, 1,3-DAG oil-based nanoemulsion delivery systems have great prospects for improving and extending emulsion properties and bioactivity as well as bioaccessibility enhancement.

Influence of Proteins on Bioaccessibility of α-Tocopherol Encapsulation within High Diacylglycerol-Based Emulsions

α-Tocopherol has been widely used in medicine, cosmetics, and food industry as a nutritional supplement and antioxidant. However, α-tocopherol showed low bioaccessibility, and there is a widespread α-tocopherol deficiency in society today. The preparation of oil-in-water emulsions with high safety and low-calorie property is necessary. The aim of this research was to investigate the effects of different protein emulsifiers (whey protein isolate (WPI), soy protein isolate (SPI), and sodium casein (SC)) on the properties of emulsions delivery system, and diacylglycerol (DAG) was picked as a low-accumulated lipid. The interfacial changes, microstructural alterations, and possible interactions of the protein-stabilized DAG emulsions were investigated during the in vitro digestion. The results show that different proteins affect the degree of digestibility and α-tocopherol bioaccessibility of the emulsions. Both WPI- and SPI-coated emulsions showed good digestibility and α-tocopherol bioaccessibility (77.64 ± 2.93%). This might be due to the strong hydrolysis resistance of WPI (β-lactoglobulin) and the good emulsification ability of SPI. The SC-coated emulsion showed the lowest digestibility and α-tocopherol bioaccessibility, this might be due to the emulsification property of hydrolysis products of SC and the potential interaction with calcium ions. This study provides new possibilities for the application of DAG emulsions in delivery systems.

Influence of milk fat on the physicochemical property of nanoencapsulated curcumin and enhancement of its biological properties thereof

Curcumin, bioactive from turmeric Curcuma longa, has been known for its therapeutic properties. However, its lipophilic nature and poor bioavailability are the constraints to harnessing its properties. Encapsulation in nano-size helps to alleviate the constraints and enhance its biological properties due to its higher surface area. The study aims to encapsulate curcumin in a nanometer size range by solubilizing in lipid (milk fat) and using milk protein as a water-soluble carrier. The lipid:curcumin ratio (1:0.05, 1:0.1, 1:0.2, 1.5:0.1, 1.5:0.2, 2.0:0.1 and 2:0.2% (w/w)) produced nanoemulsion with droplets sizes 30-200 nm. The sample containing lipid: curcumin, as 1.0:0.05 resulted in an encapsulation efficiency of 92.6%, and its binding interaction with the carrier, was KD = 4.7 µM. A high solubility of curcumin in milk fat and digestion during in vitro lipolysis increased its bioaccessibility. A simulated gastro-intestinal in vitro studies showed that cumulative release percentage of nanoencapsulated curcumin was 60% at pH 7.4 compared to 0.8% of native curcumin. The anti-microbial property of nanoencapsulated curcumin was more potent than native curcumin against food pathogenic organisms such as S. aureus, B. cereus, E. coli, B. subtilis, P. aeruginosa, P. aeruginosa, C. violaceum.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05684-5.

Recent advances in bioactive nanocrystal-stabilized Pickering emulsions: Fabrication, characterization, and biological assessment

Numerous literatures have shown the advantages of Pickering emulsion (PE) for the delivery of bioactive ingredients in the fields of food, medicine, and cosmetics, among others. On this basis, the multi-loading mode of bioactives (internal phase encapsulation and/or loading at the interface) in small molecular bioactives nanocrystal-stabilized PE (BNC-PE) enables them higher loading efficiencies, controlled release, and synergistic or superimposed effects. Therefore, BNC-PE offers an efficacious delivery system. In this review, we briefly summarize BNC-PE fabrication and characterization, with a focus on the processes of possible evolution and absorption of differentially applied BNC-PE when interacting with the body. In addition, methods of monitoring changes and absorption of BNC-PE in vivo, from the nanomaterial perspective, are also introduced. The purpose of this review is to provide an accessible and comprehensive methodology for the characterization and evaluation of BNC-PE after formulation and preparation, especially in relation to biological assessment and detailed mechanisms throughout the absorption process of BNC-PE in vivo.

Fabrication and Characterization of Botanical-Based Double-Layered Emulsion: Protection of DHA and Astaxanthin Based on Interface Remodeling

Both DHA and astaxanthin, with multiple conjugated double bonds, are considered as health-promoting molecules. However, their utilizations into food systems are restricted due to their poor water solubility and high oxidizability, plus their certain off-smell. In this study, the interactions between perilla protein isolate (PPI) and flaxseed gum (FG) were firstly investigated using multiple spectroscopies, suggesting that hydrophobic, electrostatic force and hydrogen bonds played important roles. Additionally, double-layer emulsion was constructed by layer-by-layer deposition technology and exhibited preferable effects on masking the fishy smell of algae oil. Calcium ions also showed an improving effect on the elasticity modulus of O/W emulsions and was managed to significantly protect the stability of co-delivered astaxanthin and DHA, without additional antioxidants during storage for 21 days. The vegan system produced in this study may, therefore, be suitable for effective delivery of both ω-3 fatty acid and carotenoids for their further incorporation into food systems, such as plant-based yoghourt, etc.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.