The stability and in vitro digestion of curcumin emulsions containing Konjac glucomannan

Effect of pH on the soybean whey protein-gum arabic emulsion delivery systems for curcumin: Emulsifying, stability, and digestive properties

A novel curcumin (CUR) delivery system was developed using soybean whey protein (SWP)-based emulsions, enhanced by pH-adjustment and gum arabic (GA) modification. Modulating electrostatic interactions between SWP and GA at oil/water interface, pH provides favorable charging conditions for stable distribution between droplets. GA facilitated the SWP form a stable interfacial layer that significantly enhanced the emulsifying properties and CUR encapsulation efficiency of the system at pH 6.0, which were 90.15 ± 0.67%, 870.53 ± 3.22 m2/g and 2157.62 ± 115.31%, respectively. Duncan's test revealed significant improvements in thermal, UV, oxidative, and storage stabilities of CUR (P < 0.05). At pH 6.0, GA effectively protected CUR by inhibiting SWP degradation during gastric digestion and promoting the release of CUR by decreasing steric hindrance with oil droplets during intestinal digestion, achieving the highest CUR bioaccessibility (69.12% ± 0.28%) based on Duncan's test. The SWP-GA-CUR emulsion delivery system would be a novel carrier for nutrients.

Gelatin-nanocellulose stabilized emulsion-filled hydrogel beads loaded with curcumin: Preparation, encapsulation and release behavior

In this study, the curcumin was firstly encapsulated in gelatin (GLT) and/or cellulose nanocrystals (CNC) stabilized emulsions, then further mixed with sodium alginate (SA) to form emulsion-filled hydrogel beads loaded with curcumin (Cur). The Cur-loaded emulsions showed a droplet size of 20.3-24.4 μm with a uniform distribution. Introducing CNC and/or SA increased the viscosity of emulsions accompanied by viscoelastic transition, while the modulus was reduced due to destruction of GLT gel. Cur was doubly immobilized in the hydrogel beads with >90 % of encapsulation efficiency. The results of simulated gastrointestinal tract experiments revealed that the beads possessed a good pH sensitivity and controlled release behavior to prolong the retention of Cur in the gastrointestinal tract. After 6 h of UV irradiation, the Cur-loaded emulsion-filled hydrogel beads showed a higher antioxidant activity than that of pure Cur, effectively delaying the photodegradation of Cur. In addition, the beads had better stability in aqueous and acidic environments, which was favorable for prolonging the release of Cur. These results suggest that the emulsion-filled hydrogel beads have great potential for the delivery of lipophilic bioactive molecules.

Enhanced functional properties of pea protein isolate microgel particles modified with sodium alginate: Mixtures and conjugates

Protein microgels are emerging as versatile soft particles due to their desirable interfacial activities and functional properties. In this study, pea protein isolate microgel particles (PPIMP) were prepared by heat treatment and transglutaminase crosslinking, and PPIMP were non-covalently and covalently modified with sodium alginate (SA). The effects of polymer ratio and pH on the formation of PPIMP-SA mixtures and conjugates were investigated. The optimal ratio of PPIMP and SA was found to be 20:1, with the optimal pH being 7 and 10, respectively. PPIMP-SA conjugates were prepared by Maillard reaction. It was found that ultrasound (195 W, 40 min) enhanced the degree of glycation of PPIMP, with a highest value of 37.21 ± 0.71 %. SDS-PAGE, browning intensity and FTIR data also confirmed the formation of PPIMP-SA conjugates. Compared with PPIMP and PPIMP-SA mixtures, PPIMP-SA conjugates exhibited better thermal stability, antioxidant, emulsifying and foaming properties, which opens up opportunities for protein microgel in various food applications.

Fabrication and characterization of anthocyanin-loaded double Pickering emulsions stabilized by β-cyclodextrin

Anthocyanins, one of the important water-soluble pigments, are sensitive to environmental factors, which limits the application of anthocyanins in food field. In order to overcome this limitation, double Pickering emulsions stabilized by β-cyclodextrin were developed. The optimum preparation conditions of the emulsions were determined firstly and the performance and structure of emulsions were investigated. Results showed that the optimum preparation conditions of emulsions were the ratio of (W1/O): W2 = 6:4 and 4 % β-cyclodextrin concentration. Optical microscope and confocal laser scanning microscope results confirmed that β-cyclodextrin adsorbed onto the surface of droplets forming stable double Pickering emulsions structure. In vitro gastrointestinal digestion experiments proved that double Pickering emulsions played a controlled-release effect in the small intestine. Rheological analysis proved that the emulsions exhibited elastic properties and demonstrated shear thinning behavior. The emulsions showed excellent stability under centrifugation and thermal conditions. These findings will promote anthocyanins' application in daily diet.

Advances in the construction and application of konjac glucomannan-based delivery systems

Konjac glucomannan (KGM) has been widely used to deliver bioactive components due to its naturalness, non-toxicity, excellent biodegradability, biocompatibility, and other characteristics. This review presents an overview of konjac glucomannan as a matrix, and the types of konjac glucomannan-based delivery systems (such as hydrogels, food packaging films, microencapsulation, emulsions, nanomicelles) and their construction methods are introduced in detail. Furthermore, taking polyphenol compounds, probiotics, flavor substances, fatty acids, and other components as representatives, the applied research progress of konjac glucomannan-based delivery systems in food are summarized. Finally, the prospects for research directions in konjac glucomannan-based delivery systems are examined, thereby providing a theoretical basis for expanding the application of konjac glucomannan in other industries, such as food and medicine.

Nanoliposome-Mediated Encapsulation of Chlorella Oil for the Development of a Controlled-Release Lipid-Lowering Formulation

Chlorella oil nanoliposomes (CO-NLP) were synthesized through ultrasonic injection with ethanol, and their physicochemical properties and hypolipidemic efficacy were systematically investigated. The results revealed that the mean particle size of CO-NLP was 86.90 nm and the encapsulation efficiency (EE) was 92.84%. Storage conditions at 4 °C were conducive to the stability of CO-NLP, maintaining an EE of approximately 90% even after 10 days of storage. The release profile of CO-NLP adhered more closely to the first-order kinetic model during in vitro assessments, exhibiting a slower release rate compared to free microalgae oil. In simulated in vitro digestion experiments, lipolytic reactions of CO-NLP were observed during intestinal digestion subsequent to nanoliposome administration. Notably, the inhibitory effect of CO-NLP on cholesterol esterase activity was measured at 85.42%. Additionally, the average fluorescence intensity of nematodes in the CO-NLP group was 52.17% lower than in the control group at a CO-NLP concentration of 500 μg/mL, which suggests a pronounced lipid-lowering effect of CO-NLP. Therefore, the CO-NLP exhibited characteristics of small and uniform particle size, elevated storage stability, gradual release during intestinal digestion, and a noteworthy hypolipidemic effect. These findings designate CO-NLP as a novel lipid-lowering active product, demonstrating potential for the development of functional foods.

Fabrication of compact zein-chondroitin sulfate nanocomplex by anti-solvent co-precipitation: Prevent degradation and regulate release of curcumin

The main purpose of this study was to prepare zein-chondroitin sulfate (ZC) nanocomplex by anti-solvent co-precipitation, and to encapsulate, protect and controlled-release curcumin. As the proportion of chondroitin sulfate (CS) increased, the particle size, turbidity and zeta-potential of the ZC nanocomplexes all increased. When the mass ratio of zein and CS was 10:3, the ZC nanocomplex had small particle size (129 nm) and low polydispersity index (0.3). According to FTIR, FS, CD and XRD results, zein and CS were tightly bound by electrostatic attraction, hydrophobic effect and hydrogen bonding. The ZC nanocomplex was designed to encapsulate curcumin with high encapsulation efficiency (94.7%) and loading capacity (3.8%), and also enhanced the resistance of curcumin to light and thermal degradation by 2.9 and 2.4 times. It also exhibited controlled release capability during simulated gastrointestinal digestion. These results suggested the ZC nanocomplex is a good delivery vehicle to facilitate the application of curcumin.

Investigation of the effect and mechanism of nanocellulose on soy protein isolate- konjac glucomannan composite hydrogel system

To enrich the application of nanocomposite hydrogels, we introduced two types of nanocellulose (CNC, cellulose nanocrystals; CNF, cellulose nanofibers) into the soy protein isolate(SPI)- konjac glucomannan (KGM) composite hydrogel system, respectively. The similarities and differences between the two types of nanocellulose as textural improvers of composite gels were successfully explored, and a model was developed to elaborate their interaction mechanisms. Appropriate levels of CNC (1.0 %) and CNF (0.75 %) prolonged SPI denaturation within the system, exposed more buried functional groups, improved molecular interactions, and strengthened the honeycomb structural skeleton formed by KGM. The addition of CNC resulted in greater gel strength (SKC1 2708.53 g vs. Control 810.35 g), while the addition of CNF improved the elasticity (SKF0.75 1940.24 g vs. Control 405.34 g). This was mainly attributed to the reinforcement of the honeycomb-structured, water binding and trapping, and the synergistic effect of covalent (disulfide bonds) and non-covalent interactions (hydrogen bonds, ionic bonds) within the gel network. However, the balance and interactions between proteins and polysaccharides were disrupted in the composite system with excessive CNF addition (≥0.75 %), which broken the stability of the honeycomb-like structure. We expect this study will draw attention on potential applications of CNC and CNF in protein-polysaccharide binary systems and facilitate the creation of novel, superior, mechanically strength-regulated nanofiber composite gels.

Improvement of kefir fermentation on rheological and microstructural properties of soy protein isolate gels

Soy protein isolate (SPI) has become a promising plant-based material as an animal protein products alternative. However, its application was limited due to the weak gelling properties. To investigate the effect of kefir fermentation on SPI gels properties, SPI-polysaccharide gels was produced by unfermented and kefir-fermented SPI using different concentration of KGM, chitosan, and calcium chloride in this study. Characterization of fermented SPI gels showed that fermentation by kefir grains can be applied to improve the textural strength, mechanical structure, and thermal characteristics of SPI gels. Compared to unfermented SPI gels, the water-holding capacity was remarkably enhanced to 63.11% and 65.71% in fermented SPI-chitosan gels. Moreover, the hardness of fermented SPI-KGM gels were significantly increased to 13.43 g and 27.11 g. And the cohesiveness and resilience of fermented-KGM gels were also improved than unfermented samples. Results of rheological characterization and thermogravimetric analysis revealed the strengthened mechanical features and higher thermal stability of fermented SPI gels. Additionally, the main role of hydrophobic interactions and secondary structure variations of SPI gels were demonstrated by intermolecular force measurements, Fourier-transform infrared spectroscopy, and X-ray diffraction. Moreover, the network structure was observed more compact and homogeneous performed by microstructural images in fermented SPI gels. Therefore, this research provided a novel approach combining multi-species fermentation with protein gelation to prepare SPI gel materials with improved nutrition and structural properties.

Construction of astaxanthin loaded Pickering emulsions gel stabilized by xanthan gum/lysozyme nanoparticles with konjac glucomannan from structure, protection and gastrointestinal digestion perspective

Pickering emulsion gels have demonstrated their efficacy in delivering bioactive compounds by effectively preventing droplet aggregation, Ostwald maturation, and phase separation through gel network. Astaxanthin (AST) Pickering emulsion gels stabilized by xanthan gum/lysozyme nanoparticles (XG/Ly NPs) and konjac glucomannan (KGM) were studied from rheological tests and textural analysis. The Pickering emulsion gel demonstrated the highest water holding capacity (WHC) at concentration of 2 % XG/Ly NPs, 60 % oil phase fraction, and 0.5 % KGM concentration. The presence of KGM was observed to enhance the plasticity of Pickering emulsion gels, as evidenced by the dense gel network structure formed on the surface of the droplets. Furthermore, the utilization of Pickering emulsion gels containing AST has demonstrated enhanced photostability and a protective effect on AST, as evidenced by antioxidant experiments. Moreover, the incorporation of KGM in Pickering emulsion gels has been found to reduce the release of free fatty acids (FFA) and the bioaccessibility of AST, as indicated in vitro digestion results. Overall, these findings indicate the potential of KGM-based Pickering emulsion gels as effective vehicles for the delivery of hydrophobic bioactive compounds within the food industry.

Advances in lipo-solubility delivery vehicles for curcumin: bioavailability, precise targeting, possibilities and challenges

BACKGROUND

Curcumin (Cur) is a natural pigment containing a diketone structure, which has attracted extensive attention due to its strong functional activities. However, the low solubility and poor stability of Cur limit its low bioavailability and multi-function. It is essential to develop effective measures to improve the unfavorable nature of Cur and maximize its potential benefits in nutritional intervention.

SCOPE AND APPROACH

The focus of this review is to emphasize the construction of lipo-solubility delivery vehicles for Cur, including emulsion, nanoliposome and solid liposome. In addition, the potential benefits of vehicles-encapsulated Cur in the field of precise nutrition were summarized, including high targeting properties and multiple disease interventions. Further, the deficiencies and prospects of Cur encapsulated in vehicles for precise nutrition were discussed.

KEY FINDINGS AND CONCLUSIONS

The well-designed lipo-solubility delivery vehicles for Cur can improve its stability in food processing and the digestion in vivo. To meet the nutritional requirements of special people for Cur-based products, the improvement of the bioavailability by using delivery vehicles will provide a theoretical basis for the precise nutrition of Cur in functional food.

Reversibility of freeze-thaw/re-emulsification on Pickering emulsion stabilized with gliadin/sodium caseinate nanoparticles and konjac glucomannan

The reversibility of freeze-thaw/re-emulsification of Pickering emulsion stabilized by gliadin/sodium caseinate nanoparticles (Gli/CAS NPs) was improved by adding konjac glucomannan (KGM). With the increase in the KGM concentration, the delamination of emulsions after freeze-thaw treatment was significantly improved. The microstructure showed that the presence of KGM helped to maintain the network structure of continuous phases. In particular, the particle size of the emulsion did not increase significantly after three freeze-thaw cycles when the KGM concentration was 0.6 % and the oil phase fraction was 60 %. The results of flocculation degree and coalescence degree also indicated that KGM promoted the cross-linking between particles on the surface of the droplet and increased the thickness of the interfacial film of the droplet. Rheological analysis also proved the same result: the elastic modulus of the emulsion was still larger than the viscous modulus, which showed the ideal freeze thaw reversibility. After adding KGM, the emulsion formed a strong network structure with good stability for long-term storage and reversibility for freeze-thaw cycling/re-emulsification. Thus, the emulsion has broad application prospects in food, cosmetics, and pharmaceutical fields.

Fabrication of grape seed proanthocyanidin-loaded W/O/W emulsion gels stabilized by polyglycerol polyricinoleate and whey protein isolate with konjac glucomannan: Structure, stability, and in vitro digestion

In this work, the effects of konjac glucomannan (KGM) concentrations on microstructure, gel properties, stability and digestibility of water-in-oil-in-water emulsion gels stabilized by polyglycerol polyricinoleate and whey protein isolate were investigated. Visual appearance indicated that a non-layered double emulsion gel was formed when KGM increased to 0.75%. Emulsion gels with 1.5% KGM showed the highest encapsulation, freeze-thaw and photochemical stability due to the formation of the smallest droplets, which were supported by microscopic observations. Moreover, the addition of KGM improved water holding capacity, rheological and texture properties of emulsion gels. Particularly, at 1.5% or 1.75% KGM, color and potential of hydrogen showed the most stable level after 14 days of storage. During in vitro digestion, KGM delayed the hydrolysis of protein and oil droplets, and then improved the bioavailability of grape seed proanthocyanidin. These results promoted the application of KGM in emulsion gels and the encapsulation of nutraceuticals.

Influence of fish skin gelatin-sodium alginate complex stabilized emulsion on benzyl isothiocyanate stability and digestibility in vitro and in vivo

BACKGROUND

An emulsion delivery system for benzyl isothiocyanate (BITC) was prepared using fish skin gelatin (FSG) and sodium alginate (Alg). The effects of the FSG-Alg complex on the emulsion stability and BITC release pattern from the emulsion were investigated in vitro and in vivo.

RESULTS

The storage stability and embedding rate of the 10 g kg^-1 FSG and 2.5 g kg^-1 Alg (FSG-Alg) emulsion were the highest among all samples. The FSG-Alg complex provided BITC a better protection during in vitro digestion. The microstructure of the FSG-Alg emulsions was more stable during in vitro digestion, and the bioaccessibility and retention rate of BITC were much higher compared to those of the FSG emulsion. The results of the ex vivo everted gut sac of rat intestine study showed that the FSG-Alg emulsion significantly increased the BITC absorption rate in the duodenum.

CONCLUSION

The FSG-Alg emulsion delivery system is a highly stable system for the delivery of BITC that improves the bioaccessibility of BITC and promotes its absorption in the duodenum. © 2022 Society of Chemical Industry.

Advanced Coatings with Antioxidant and Antibacterial Activity for Kumquat Preservation

An active coating is one of the best ways to maintain the good quality and sensory properties of fruits. A new active coating was prepared by incorporating curcumin and phloretin into the konjac glucomannan matrix (KGM-Cur-Phl). The fourier infrared spectroscopy, rheology and differential scanning calorimetry confirmed the successful fabrication of this coating. This coating showed excellent antioxidant activity revealed by the 95.03% of ABTS radicals scavenging ratio and 99.67% of DPPH radicals scavenging ratio. The result of bacteria growth curves showed that it could effectively inhibit the growth of Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Salmonella typhimurium. The results of firmness, titratable acid and pH showed that it effectively prolonged the shelf life of kumquat. A novel konjac glucomannan-based active coating was provided.

Fabrication and characterization of a cannabidiol-loaded emulsion stabilized by a whey protein-maltodextrin conjugate and rosmarinic acid complex

A cannabidiol (CBD)-loaded oil-in-water emulsion stabilized by a whey protein (WP)-maltodextrin (MD) conjugate and rosmarinic acid (RA) complex was fabricated, and its stability characteristics were investigated under various environmental conditions. The WP-MD conjugates were formed via dry-heating. The interaction between WP and MD was assessed by browning intensity, reduced amount of free amino groups, the formation of high molecular weight components in sodium dodecyl sulfate-PAGE, and changes in secondary structure of whey proteins. The WP-MD-RA noncovalent complex was prepared and confirmed by fluorescence quenching and Fourier-transform infrared spectroscopy spectra. Emulsions stabilized by WP, WP-MD, and WP-RA were used as references to evaluate the effect of WP-MD-RA as a novel emulsifier. Results showed that WP-MD-RA was an effective emulsifier to produce fine droplets for a CBD-loaded emulsion and remarkably improved the pH and salt stabilities of emulsions in comparison with WP. An emulsion prepared with WP-MD-RA showed the highest protection of CBD against UV and heat-induced degradation among all emulsions. The ternary complex kept emulsions in small particle size during storage at 4°C. Data from the current study may offer useful information for designing emulsion-based delivery systems which can protect active substance against environmental stresses.

Synthesis and characterization of lotus seed protein-based curcumin microcapsules with enhanced solubility, stability, and sustained release

BACKGROUND

Lotus seed protein (LSP) was extracted from lotus seed and used to encapsulate curcumin with or without complexing with pectin. The physicochemical properties of LSP-based microcapsules, including solubility, stability, and in vitro sustained release, were determined. The mechanism of interaction between curcumin, LSP, and pectin was revealed.

RESULTS

The encapsulation efficiency of curcumin was found to depend on LSP concentration and was highest (86.32%, w/w) at 50 mg mL^-1 . The curcumin in curcumin-LSP and curcumin-LSP-pectin powder particles achieved a solubility of 75.15% and 81.39%, respectively, which was a remarkable enhancement. The microencapsulation with LSP and LSP-pectin matrix showed a significant improvement in the antioxidant activity, photostability, thermostability, and storage stability of free curcumin. The microencapsulated curcumin showed sustained control release at the gastric stage and burst-type release in the subsequent intestinal stage, presenting cumulative release rates of 64.3% and 72.4% from curcumin-LSP and curcumin-LSP-pectin particles after gastrointestinal digestion. The LSP-pectin complex produced microcapsules with higher solubility, smaller particle size, enhanced physicochemical stability, and increased bioaccessibility. Fourier transform infrared, circular dichroism spectra, and differential scanning calorimetry data indicated that the encapsulated curcumin interacted with LSP and pectin mainly through hydrogen bonding, hydrophobic, and electrostatic interactions.

CONCLUSION

This work shows that LSP can be an alternative encapsulant for the delivery of hydrophobic nutraceuticals with enhanced solubility, stability, and sustained release. The results may contribute to the design of novel food-grade delivery systems based on LSP vehicles, thereby broadening the applications of LSP in the fields of functional food. © 2021 Society of Chemical Industry.

Impact of polysaccharide mixtures on the formation, stability and EGCG loading of water-in-oil high internal phase emulsions

Water-in-oil (W/O) high internal phase emulsions (HIPEs) were prepared using polyglycerol polyricinoleate (PGPR) and polysaccharide blends consisting of konjac glucomannan (KGM) and octenyl succinic anhydride starch (OSA-starch). The formation, stability, and functionality of these emulsions were varied by adjusting the ratio of KGM and OSA-starch. Interfacial tension measurements indicated that the OSA-starch co-adsorbed to the water-oil interface with PGPR, which would have led to the formation of a polysaccharide-layer that helped prevent separation of the HIPEs. The centrifugal stability, rheological and microstructural results indicated that the W/O HIPEs exhibited well pH, ionic and thermal stability. The encapsulation efficiency, stability, and bioaccessibility of the EGCG in the W/O HIPEs were evaluated by using EGCG as a model hydrophilic nutraceutical. This study provides useful insights into the utilization of emulsion technology to reduce the fat content and improve the nutritional profile of foods with oily continuous phases, such as spreads.

Influence of Pasteurization and Storage on Dynamic In Vitro Gastric Digestion of Milk Proteins: Quantitative Insights Based on Peptidomics

It is important to evaluate the nutritional quality of milk during the shelf-life, especially during home storage, from a consumer viewpoint. In this study, we investigated the impact of pasteurization (85 °C/15 s) and subsequent storage (at 4 °C for 7 days) on the coagulation behavior of milk and protein digestibility in a dynamic in vitro gastric digestion test. A high level of hydration in curd formed in pasteurized milk upon 7-day cold storage compared to raw and pasteurized milk, indicating fast pepsin diffusion in the interior of curds, increasing the hydrolysis rate. The digesta collected at various time points throughout the gastric digestion were studied using o-phthaldialdehyde (OPA), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), liquid chromatography tandem mass spectrometry (LC-MS/MS), and amino acid analysis. These results showed that milk proteins were hydrolyzed quickly upon a long period of cold storage. Additionally, qualitative and quantitative results obtained using LC-MS/MS exhibited significant differences between samples, especially in pasteurized milk upon cold storage. Processing and storage played a decisive role in bioactive peptide generation. Such knowledge could provide insights into and directions for the storage of pasteurized milk for further clinical studies on protein bioavailability and the generation of bioactive peptides for desired health outcomes.

Designing multiple bioactives loaded emulsions for the formulations for diets of elderly

In this study, a stable double emulsion loaded with essential bioactives for the elderly was prepared using a two-step mechanical emulsification process.