Modulation of physicochemical stability and bioaccessibility of β-carotene using alginate beads and emulsion stabilized by scallop (Patinopecten yessoensis) gonad protein isolates

Encapsulation of β-carotene in Pickering emulsions stabilized by self-aggregated chitosan nanoparticles: Factors affecting β-carotene stability

For conventional emulsions used to encapsulate easily degradable bioactive compounds, achieving small droplet size and high encapsulation capacity is a challenging. Pickering emulsions stabilized by self-aggregated chitosan particles may offer high encapsulation efficiency due to the robust mechanical barrier formed by solid particles adsorbed at the oil-water interface. Therefore, the effects of pH, chitosan concentration, oil volume fraction, homogenization pressure, and homogenization cycle on the stability of chitosan Pickering emulsions and the degradation of β-carotene were investigated. Effective interfacial adsorption of chitosan nanoparticles and moderate homogenization intensity facilitated the formation of small emulsion droplets. Unlike conventional emulsions, chitosan Pickering emulsions with smaller droplets provided enhanced protection for β-carotene. This enhancement was primarily attributed to the improved interfacial coverage of chitosan nanoparticles with smaller droplet sizes, which was advantageous for β-carotene protection. The optimal conditions for preparing β-carotene-loaded chitosan Pickering emulsions were as follows: pH 6.5, chitosan concentration of 1.0 wt%, oil volume fraction of 20 %, homogenization pressure of 90 MPa, and 6 homogenization cycles. These findings indicate that chitosan Pickering emulsions are well-suited for encapsulating β-carotene with both small droplet size and high encapsulation efficiency.

The construction of Moringa oleifera seed protein emulsion: in vitro digestibility and delivery of β-carotene

BACKGROUND

β-Carotene (BC) is difficult to apply effectively in the food industry due to its low solubility and bioavailability. This work aimed to fabricate Moringa oleifera seed protein (MOSP) stabilized emulsions as delivery vehicles for BC and investigate the effect of aqueous phase conditions including pH and ionic strength on this system.

RESULTS

All MOSP samples were positively charged and the particle size of MOSP increased with the increase of pH. At pH 5.0 and 0.2 mol L-1 sodium chloride (NaCl), the MOSP emulsion demonstrated the highest stability coefficient and minimal creaming index, while exhibiting a lower release rate in vitro digestion. The rheological behavior of all MOSP emulsions within the frequency range of 0.1-10 Hz was dominated by viscoelasticity, forming an elastic network structure through dispersed droplets. Additionally, the MOSP emulsion loaded with BC prepared at pH 5.0 and 0.2 mol L-1 NaCl displayed enhanced ultraviolet light stability (52.31 ± 0.03% and 51.86 ± 0.05%) as well as thermal stability (72.39 ± 8.67% and 86.78 ± 10.69%). Furthermore, the BC in the emulsion at pH 7.0 exhibited favorable stability (65.14 ± 0.02%) and optimal bioaccessibility (40.30 ± 0.04%) in vitro digestion.

CONCLUSION

The results provided reference data for utilizing MOSP as a novel emulsifier and broadening the application of BC in the food industry. © 2024 Society of Chemical Industry.

Synthesis and characterization of ion-induced sodium alginate/soy protein isolate microgels for the controlled release

In this study, sodium alginate/ soy protein isolate (SPI) microgels cross-linked by various divalent cations including Cu2+, Ba2+, Ca2+, and Zn2+ were fabricated. Cryo-scanning electron microscopy observations revealed distinctive structural variations among the microgels. In the context of gastric pH conditions, the degree of shrinkage of the microgels followed the sequence of Ca2+ > Ba2+ > Cu2+ > Zn2+. Meanwhile, under intestinal pH conditions, the degree of swelling was ranked as Zn2+ > Ca2+ > Ba2+ > Cu2+. The impact of these variations was investigated through in vitro digestion studies, revealing that all microgels successfully delayed the release of β-carotene within the stomach. Within the simulated intestinal fluid, the microgel cross-linked with Zn2+ exhibited an initial burst release, while those cross-linked with Cu2+, Ba2+, or Ca2+ displayed a sustained release pattern. This research underscores the potential of sodium alginate/SPI microgels cross-linked with different divalent cations as efficient controlled-release delivery systems.

Stability and Bioaccessibility of Carotenoids from Sea Buckthorn Pomace Encapsulated in Alginate Hydrogel Beads

Carotenoids, the natural pigments that confer the bright orange color of sea buckthorn berries, are also associated with several health benefits, such as antioxidant activity and skin and eye protection. Due to their lipophilic nature and localization, carotenoids are largely retained in the sea buckthorn pomace (SBP) resulting from juice production. Carotenoids from SBP (70.03 mg/100 g DW), extracted and characterized by HPLC-PDA, contained zeaxanthin (free and esterified) and beta-carotene as major compounds. The SBP carotenoids-enriched sunflower oil was further encapsulated in Ca-alginate hydrogel beads (98.4% encapsulation efficiency) using ionotropic gelation. The hydrogel beads were characterized by confocal laser scanning microscopy and scanning electron microscopy. Fairly good stability (>64%) of the encapsulated carotenoids in the alginate hydrogel beads during storage (30 days, 4 °C and 25 °C) was found, with zeaxanthin esters being the most stable compounds, for all the experimental conditions. The bioaccessibility of the total carotenoids (INFOGEST protocol) was 42.1 ± 4.6% from hydrated, and, respectively, 40.8 ± 4% from dehydrated SBP alginate hydrogel beads. The addition of yogurt to the dehydrated hydrogel beads had a positive effect on the bioaccessibility of free and esterified zeaxanthin, but not on that of the carotenes. In conclusion, SBP is a valuable source of carotenoids which can be protected by encapsulation in alginate hydrogel beads, thus still retaining a good bioaccessibility.

Co-encapsulation of collagen peptide and astaxanthin in WG/OG/W double emulsions-filled alginate hydrogel beads: Fabrication, characterization and digestion behaviors

The double emulsions-filled hydrogel beads delivery systems with controlled lipolysis and sustained-release property of co-encapsulated bioactive substances will be highly desired. Herein, the water-in-oil-in-water emulsion with gelled inner water phase and oil phase (WG/OG/W) filled hydrogel beads as a novel co-delivery system were developed with varied concentrations of rice bran wax and W/O emulsions to achieve effectively controlled release of lipolysis and nutraceuticals. Interestingly, the gelation of oil phase triggered by rice bran wax could enhance the storage stability of WG/OG/W emulsions due to the enhanced viscoelastic property. Increasing the mass fractions of W/O emulsions improved the stability of double emulsions due to increased viscosity and decreased particle size. Cryo-SEM observation showed that the double emulsion droplets were scattered in the three-dimensional network of alginate gel beads. Increased the addition of rice bran wax or W/O emulsions, the encapsulation efficiency of collagen peptide and astaxanthin was significantly improved. The in vitro digestion results indicated that increasing the concentrations of rice bran wax and W/O emulsion fractions in WG/OG/W emulsion-filled gel beads could effectively delay the release extent of free fatty acids and encapsulated nutraceuticals. The presence of rice bran wax contributed to increase the bioaccessibility of collagen peptide and astaxanthin.

Effect of wall material on lipophilic functional compounds of high oleic palm oil emulsions encapsulated by Refractance Window drying

High-oleic palm oil is a food-grade oil with desirable properties, as it is characterised by having an oleic acid concentration above 50 % and a high vitamin E and provitamin A content. This study investigated the effect of different combinations of two wall materials (whey protein (WP) and Capsul®, a commercial octenyl succinic anhydride modified starch (OSA-MS)) on the concentration of provitamin A, vitamin E and oleic acid, and the physical properties of high oleic palm oil emulsions encapsulated by Refractance Window drying technology. Wall material composition significantly affected (p < 0.05) all response variables, and R2 values were above 0.75 for all responses. Phytonutrient preservation showed its highest at an OSA-MS: WP concentration ratio of 1: 3. Optimal results were achieved (minimum moisture content, water activity and hygroscopicity, and maximum encapsulation efficiency and phytonutrient preservation) at an OSA-MS concentration of 8.13 % and WP concentration of 91.87 %. Flakes were obtained as a solid structure that protects oil's phytonutrients with 94 %, 75 % and 87 % of preservation of oleic acid, vitamin E and carotenoids, respectively. It shows that the wall material combination and encapsulation technique are suitable for obtaining lipophilic functional compounds.

Alginate Gel-Based Carriers for Encapsulation of Carotenoids: On Challenges and Applications

Sodium alginate is one of the most interesting and the most investigated and applied biopolymers due to its advantageous properties. Among them, easy, simple, mild, rapid, non-toxic gelation by divalent cations is the most important. In addition, it is abundant, low-cost, eco-friendly, bio-compatible, bio-adhesive, biodegradable, stable, etc. All those properties were systematically considered within this review. Carotenoids are functional components in the human diet with plenty of health benefits. However, their sensitivity to environmental and process stresses, chemical instability, easy oxidation, low water solubility, and bioavailability limit their food and pharmaceutical applications. Encapsulation may help in overcoming these limitations and within this review, the role of alginate-based encapsulation systems in improving the stability and bioavailability of carotenoids is explored. It may be concluded that all alginate-based systems increase carotenoid stability, but only those of micro- and nano-size, as well as emulsion-based, may improve their low bioaccessibility. In addition, the incorporation of other biopolymers may further improve encapsulation system properties. Furthermore, the main techniques for evaluating the encapsulation are briefly considered. This review critically and profoundly explains the role of alginates in improving the encapsulation process of carotenoids, suggesting the best alternatives for those systems. Moreover, it provides a comprehensive cover of recent advances in this field.

pH-Shifting combined with ultrasound treatment of emulsion-filled β-conglycinin gels as β-carotene carriers: Effect of emulsion concentration on gel properties

In this work, emulsion-filled gels were prepared from natural and pH-shifting combined with ultrasound β-conglycinin (7S) as emulsifiers. The emulsifier modification and emulsion concentrations (5, 10, 15, 20 wt%) were evaluated on the structural and β-carotene release properties of the gels. Compared to the 7S hydrogel, the emulsion-filled gels exhibited better water-holding and textural properties. The 7S modification and the increase in emulsion concentration resulted in altered water distribution and improved microstructure and rheological properties of the emulsion-filled gels. The dense and homogeneous gel network was formed at an emulsion content of 15 wt%. The gels were regulated by different release kinetics in a simulated gastrointestinal environment. M-15 showed the highest bioaccessibility and chemical stability (72.25% and 89.87%) with good slow-release properties of β-carotene. These results will guide the development of encapsulated delivery systems for gel food products.

Effect of gelation technique on lipid digestibility of emulsion-loaded alginate microparticles: a systematic review and meta-analysis

Alginate microparticles fabricated via calcium gelation or layer-by-layer assembly are commonly used for encapsulating emulsions. In this study, the impact of these two gelation methods on the lipid digestibility of emulsions was reviewed through a systematic screening of relevant studies. From the literature search (Scopus, PubMed, and Web of Science databases), 604 records were screened and 25 articles were included in the analysis. The fold change of free fatty acid release rate at the end of in vitro digestion process between alginate-encapsulated emulsion and emulsions not encapsulated by alginate was calculated for calcium gelation (weighted mean of response ratio 0.64, 95% CI 0.54-0.75) and layer-by-layer assembly (weighted mean of response ratio 0.89, 95% CI 0.81-0.98). Alginate-calcium hydrogels showed stronger inhibition of the extent of lipid digestion than alginate-coated multilayer emulsions. The structural and particle size differences between alginate microparticles acquired using different techniques may contribute to this phenomenon.

Producing mixed-soy protein adsorption layers on alginate microgels to controlled-release β-carotene

In this study, the effects of soy protein isolate (SPI) on the morphology, encapsulation efficiency, storage stability, swelling behavior, and in vitro digestion behavior of calcium alginate (CA) microgels were investigated. CA and calcium alginate-SPI (CAS) microgels with encapsulated β-carotene were prepared by extruding a mixture of alginate and SPI using a co-extrusion technique, followed by cross-linking with Ca²⁺. All microgels exhibited homogeneous sizes and spherical shapes, and CAS microgels showed high levels of protein loading efficiency. The encapsulation efficiency and storage stability of β-carotene within CAS microgels were higher than those within CA microgels. The introduction of SPI into CAS microgels resulted in a higher degree of gel size shrinkage in gastric fluid and a lower degree of swelling in intestinal fluid compared to CA microgels. In vitro digestion was conducted to investigate the effects of the addition of SPI on the release behavior of CA and CAS microgels. Results obtained showed that CAS microgels were more resistant to simulated gastric fluid than CA microgels. Cryo-scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) observations indicated that the release behavior was dependent on the porosity of the CA and CAS microgels, and the porosity was influenced by the concentration of SPI. This study showed that the introduction of SPI to CA microgels can lead to the development of an effective controlled release delivery system.

Improving the in vitro and in vivo bioavailability of pterostilbene using Yesso scallop gonad protein isolates-epigallocatechin gallate (EGCG) conjugate-based emulsions: effects of carrier oil

This study investigated the influence of carrier oils on the in vitro and in vivo bioavailability of PTE encapsulated in scallop gonad protein isolates (SGPIs)-epigallocatechin gallate (EGCG) conjugate stabilized emulsions. The SGPIs-EGCG stabilized emulsions were subjected to an in vitro simulated digestion, and the resulting corn oil and MCT micelles were used to evaluate the PTE transportation using the Caco-2 cell model. Both emulsions remarkably improved the bioaccessibility of PTE in the micelle phase. Nevertheless, corn oil emulsions increased trans-enterocyte transportation of PTE more efficiently than MCT emulsions. Furthermore, the maximum plasma concentrations of PTE and its metabolites in mice fed with PTE emulsions were prominently higher than those in mice fed with PTE solution, while the in vivo metabolic patterns of PTE in different oil-stabilized emulsions were different. Therefore, SGPIs-EGCG stabilized emulsions could enhance the bioavailability of PTE through controlled release, in which corn oil is more suitable than MCT.

Preparation and Evaluation of Undaria pinnatifida Nanocellulose in Fabricating Pickering Emulsions for Protection of Astaxanthin

Pickering emulsions stabilized from natural sources are often used to load unstable bio-active ingredients, such as astaxanthin (AXT), to improve their functionality. In this study, AXT-loaded Pickering emulsions were successfully prepared by 2,2,6,6-tetramethy-1-piperidine oxide (TEMPO)-oxidized cellulose nanofibers (TOCNFs) from Undaria pinnatifida. The morphology analysis showed that TOCNFs had a high aspect ratio and dispersibility, which could effectively prevent the aggregation of oil droplets. The stable emulsion was obtained after exploring the influence of different factors (ultrasonic intensity, TOCNFs concentration, pH, and ionic strength). As expected, AXT-loaded Pickering emulsions showed good stability at 50 °C and 14 days of storage. The results of simulated in vitro digestion showed that the emulsions exhibited higher release of free fatty acids (FFAs) and bioaccessibility of AXT than those in sunflower oil. Hence, our work brought new insights into the preparation of Pickering emulsions and their applications in protection and sustained, controlled release of AXT.

The Layered Encapsulation of Vitamin B2 and β-Carotene in Multilayer Alginate/Chitosan Gel Microspheres: Improving the Bioaccessibility of Vitamin B2 and β-Carotene

This research underlines the potential of alginate multilayered gel microspheres for the layered encapsulation and the simultaneous delivery of vitamin B₂ (VB) and β-carotene (BC). Chitosan was used to improve the stability and controlled release ability of alginate-based gel microspheres. It was shown that a clear multilayered structure possessed the characteristics of pH response, and excellent thermal stability. The sodium alginate concentration and the number of layers had notable effects on mechanical properties and particle size of gel microspheres. Fourier-transform infrared spectroscopy and X-ray diffraction analyses further proved that VB and BC were encapsulated within the gel microspheres. Compared with the three-layer VB-loaded gel microspheres, the total release of VB from the three-layer VB and BC-loaded gel decreased from 93.23% to 85.58%. The total release of BC from the three-layer VB and BC-loaded gel increased from 66.11% to 69.24% compared with three-layer BC-loaded gel. The simultaneous encapsulation of VB and BC in multilayered gel microspheres can markedly improve their bioaccessibility and bioavailability. These results showed the multilayer gel microspheres synthesized herein have potential for applications in the layered encapsulation and simultaneous delivery of various bioactive substances to the intestinal tract.

Enhancing bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems

The consumption of foods rich in antioxidants, vitamins, minerals including carotenoids etc. can boost the immune system to help fight off various infections including SARS- CoV 2 and other viruses. Carotenoids have been gaining attention particularly in food and pharmaceutical industries owing to their diverse functions including their role as pro-vitamin A activity, potent antioxidant properties, and quenching of reactive oxygen (ROS), such as singlet oxygen and lipid peroxides within the lipid bilayer of the cell membrane. Nevertheless, carotenoids being lipophilic, have poor solubility in aqueous medium and are also chemically instable. They are susceptible to degrade under stimuli environmental conditions during food processing, storage and gastrointestinal passage. They also exhibit poor oral bioavailability, thus, their applications in aqueous-based foods are limited. As a consequent, suitable delivery systems including colloids-based are needed to enhance the solubility, stability and bioavailability of carotenoids. This review presents challenges of incorporation and delivery of carotenoids focusing on stability and factors affecting bioavailability. Furthermore, designed factors impacting bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems are explicitly explained. Each delivery system exhibits its own advantages and disadvantages; thus, the delivery systems should be designed based on their targets and their further applications.

Alginate-based delivery systems for food bioactive ingredients: An overview of recent advances and future trends

Due to its advantagessuch as ionic crosslinking, pH responsiveness, excellent biocompatibility, biodegradability and low price, alginate has become one of the most important natural polysaccharides extensively used in constructing desired delivery systems for food bioactive ingredients. In this review, the fundamental knowledge of alginate as a building block for construction of nutraceutical delivery systems is introduced. Then, various types of alginate-based nutraceutical delivery systems are classified and summarized. Furthermore, the future trends of alginate-based delivery systems are highlighted. Currently, alginate-based delivery systems include hydrogel, emulsion, emulsion-filled alginate hydrogel, nanoparticle, microparticle, core-shell particle, liposome, edible film, and aerogel. Although alginate has been widely used in the fabrication of food bioactive ingredient delivery systems, further efforts and improvements are still needed. For this purpose, the future perspectives of alginate-based delivery systems are discussed. The feasible research trends of alginate-based delivery systems include the development of novel large-scale commercial preparation technology, multifunctional delivery system based on alginate, alginate oligosaccharide-based delivery system and alginate-based oleogel. Overall, the objective of this review is to provide useful guidance for rational design and application of alginate-based nutraceutical delivery systems in the future.