Physicochemical stability and in vitro bioaccessibility of β-carotene emulsions stabilized with arabinoxylan hydrolysates-soy protein isolate conjugates

Lipase-Responsive Lignin Composite Nanoparticles for the Delivery of Insoluble Bioactives

Low solubility and chemical instability are the main problems with insoluble bioactives. Lignin, with its exceptional biological properties and amphiphilicity, holds promise as a delivery system material. In this study, glycerol esters were incorporated into alkali lignin (AL) through ether and ester bonds, resulting in the successful synthesis of three hydrophobically modified alkali lignins (AL-OA, AL-OGL, and AL-SAN-OGL). Subsequently, lignin composite nanoparticles (LNPs@BC) encapsulating β-carotene were prepared using antisolvent and sonication techniques. The encapsulation rates were determined to be 37.69 ± 2.21%, 84.01 ± 5.55%, 83.82 ± 5.23%, and 83.11 ± 5.85% for LNP@BC-1, LNP@BC-2, LNP@BC-3, and LNP@BC-4, respectively, with AL, AL-OA, AL-OGL, and AL-SAN-OGL serving as the wall materials under optimized preparation conditions. The antioxidant properties and UV-absorbing capacity of the four lignins were characterized, demonstrating their efficacy in enhancing the oxygen and photostability of β-carotene. Following 6 h of UV irradiation, LNP@BC-4 exhibited a retention rate of 83.03 ± 2.85% for β-carotene, while storage under light-protected conditions at 25 °C for 7 days retained 73.33 ± 7.62% of β-carotene. Furthermore, the encapsulated β-carotene demonstrated enhanced thermal and storage stability. In vitro release experiments revealed superior stability of LNPs@BC in simulated gastric fluid (SGF), with β-carotene retention exceeding 77% in both LNP@BC-3 and LNP@BC-4. LNP@BC-4 exhibited the highest bioaccessibility in simulated intestinal fluid (SIF) at 46.96 ± 0.80%, that LNP@BC-1 only achieved 10.87 ± 0.90%. The enzymatic responsiveness of AL-OGL and AL-SAN-OGL was confirmed. Moreover, LNPs@BC exhibited no cytotoxicity toward L929 cells and demonstrated excellent hemocompatibility. In summary, this study introduces a novel enzyme-responsive modified lignin that has promising applications in the fields of food, biomedicine, and animal feed.

Hydrolysates with emulsifying properties prepared from protein wastes using microbial protease

Plant-based protein hydrolysates have found applications in food industry for emulsification, foaming, and increasing shelf life of food products. The objective of this study is to isolate protease-secreting bacteria hydrolyzing protein waste, and subjecting the resultant hydrolysates for the characterization for application in the food industry. Peanut cake hydrolysates were prepared using proteases from two microorganisms selected for the purpose, viz., Aneurinibacillus migulanus, VITPM11 and Aneurinibacillus aneurinilyticus, VITPS07. The cleavage specificity of the proteases from VITPM11 and VITPS07 were found to be like plasmin and elastase respectively. The cleaving sites of proteases for peanut proteins were predicted using expasy tool. The protease of VITPM11 had maximal activity of 325.8 ± 0.1 U/mL in peanut-cake media. The degree of hydrolysis (32.03 ± 0.89%), solubility (88.5 ± 1.18%), emulsion stability index (89.76 ± 2.80) and foaming stability (68.67 ± 1.53%) properties of VITPM11 protease correlated well with results from bioinformatic studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01490-z.

Pickering emulsions stabilized by ternary complexes involving curcumin-modified zein and polysaccharides with different charge amounts for encapsulating β-carotene

In this research, zein was modified with curcumin to obtain covalent and non-covalent complexes. They were further covered with polysaccharides (gum arabic or gum karaya) possessing different surface charge amounts to obtain ternary nanoparticles for preparing novel antioxidant Pickering emulsions. The addition of curcumin to the zein-polysaccharide system significantly retarded the UV degradation of the encapsulated β-carotene (maximum retention ∼ 97%) and effectively inhibited the lipid oxidation of the emulsions. In vitro gastrointestinal digestion assays showed that gum karaya significantly delayed the release of free fatty acids, thereby improving the bioaccessibility of β-carotene (the highest bioavailability ∼ 38%). By comparing the performance of the complex particles, the weakly charged polysaccharides were superior to the highly charged ones, while zein-curcumin covalent binding was superior to non-covalent binding in the above experiments. This study provides innovative perspectives on the use of novel Pickering emulsions to provide ideal protection and bioavailability of lipophilic nutraceuticals.

Wheat bran arabinoxylan-soybean protein isolate emulsion-filled gels as a β-carotene delivery carrier: Effect of polysaccharide content on textural and rheological properties

This study aimed to investigate the effects of different wheat bran arabinoxylan (WBAX) concentrations (1, 2, 3, and 4 wt%) on the structural and physicochemical properties of WBAX-soybean protein isolate (SPI) emulsion-filled gels (EFGs) prepared using laccase and heat treatment. The properties of the various gels as well as their microstructure, rheology, and in vitro digestion behaviors were investigated. Results showed that WBAX-SPI EFGs with a 3 wt% WBAX concentration had a smooth and uniform appearance, high water holding capacity (98.5 ± 0.2 %), and enhanced mechanical properties. Rheological experiments suggested that a stronger and closer gel network was formed at 3 wt% WBAX concentration. Fourier transform infrared spectroscopy showed that laccase and heat treatment not only catalyzed the intramolecular crosslinking of WBAX and SPI, respectively, but also promoted the interaction between WBAX and SPI. Confocal laser scanning microscopy revealed that the WBAX gel network was interspersed within the SPI network. The interactions contributing to the gelation analysis revealed that chemical (disulfide bond) and physical (hydrogen bond and hydrophobic) interactions promoted the formation of denser EFGs. Furthermore, the WBAX-SPI EFGs provided a β-carotene bioaccessibility of 21.8 ± 0.6 %. Therefore, our study suggests that WBAX-SPI EFGs hold promising potential for industrial applications in the delivery of β-carotene.

Modulation of physicochemical properties of lipid droplets using soy protein isolate and lactoferrin interfacial coatings

In order to improve the physicochemical stability of soy protein isolate (SPI) emulsion, lactoferrin (LF) was used to modify the interface layer. The stable multilayer emulsion can be formed when the content of lactoferrin is 0.5% at pH 5. The emulsion with good stability was at pH 3-7, and it was also stable to temperature change. The FFAs release of SPI emulsion and LF-SPI emulsion was 103.9% and 103.7%, respectively. The results showed that the lactoferrin layer did not hinder the digestion of oil and the bioaccessibility of carotenoids, but lactoferrin layer improved the physicochemical stability of SPI emulsions. This work provides information valuable in the design of emulsion formulations for applications in the food, pharmaceutical, and personal care industries.

Combination modes impact on the stability of β-carotene-loaded emulsion constructed by soy protein isolate, β-glucan and myricetin ternary complex

A β-carotene rich emulsion with improved physical and chemical stability was obtained in this study, using different types of protein-polysaccharide-polyphenol ternary complexes as novel emulsifiers. The ternary complexes were prepared by covalent or non-covalent binding of soy protein isolate (SPI), β-glucan (DG) and myricetin (MC), which were evidenced to be stable. It was indicated that the emulsion stabilized by covalent complex of SPI, DG and MC, exhibited higher zeta-potential and smaller particle size than those stabilized by non-covalent complex. Furthermore, the covalent complexes prepared from different addition sequences showed different efficiencies in stabilizing the emulsion, in which SPI-DG-MC and SPI-MC-DG-stabilized emulsions possess better stability, emulsifying activity and storage resistance under adverse environmental treatment, with CI values of 62.7% and 64.3% after 25 days, respectively. According to oxidative stability and rheology analysis of the emulsions, it was found that the SPI-MC-DG complex prepared at the ratio of 4:2:1 was more stable with relatively less lipid oxidation products and a tighter stacking structure, and the final LH value was 39.98 mmol/L and the MDA value was 6.34 mmol/L. These findings implied that the ternary complex has the potential to deliver fat-soluble active ingredient by means of emulsion, but which depends on the mode and sequence of the molecular interactions.

Characterization of polysaccharide from Lonicera japonica Thunb leaves and its application in nano-emulsion

The polysaccharides in honeysuckle leaves (PHL) were separated and characterized for the first time. The nano-emulsion stabilized by PHL and whey protein isolate (WPI) were also fabricated based on the ultrasonic method. The results indicated that PHL was mainly composed of glucose (47.40 mol%), galactose (19.21 mol%) and arabinose (20.21 mol%) with the weight-average molecular weight of 137.97 ± 4.31 kDa. The emulsifier concentration, WPI-to-PHL ratio, ultrasound power and ultrasound time had significant influence on the droplet size of PHL-WPI nano-emulsion. The optimal preparation conditions were determined as following: emulsifier concentration, 1.7%; WPI/PHL ratio, 3:1; ultrasonic power, 700 W; ultrasonic time, 7 min. Under the above conditions, the median diameter of the obtained nano-emulsion was 317.70 ± 5.26 nm, close to the predicted value of 320.20 nm. The protective effect of PHL-WPI emulsion on β-carotene against UV irradiation was superior to that of WPI emulsion. Our results can provide reference for the development of honeysuckle leaves.

A nano-Liposomal formulation potentiates antioxidant, anti-inflammatory, and fibrinolytic activities of Allolobophora caliginosa coelomic fluid: formulation and characterization

BACKGROUND

Coelomic fluid, a pharmacologically active compound in earthworms, exhibits a range of biological activities, including antioxidant, anti-inflammatory, and anticancer. However, the biological activities exerted by the coelomic fluid can be restrained by its low bioavailability and stability. Liposomes are progressively utilized as an entrapment system for natural bioactive compounds with poor bioavailability and stability, which could be appropriate for coelomic fluid. Thus, the present study was designed to fabricate, characterize, and evaluate the stability of liposomal formulation for Allolobophora caliginosa coelomic fluid (ACCF) as a natural antioxidant compound.

METHODS

The ACCF-liposomes were developed with a subsequent characterization of their physicochemical attributes. The physical stability, ACCF release behavior, and gastrointestinal stability were evaluated in vitro. The biological activities of ACCF and its liposomal formulation were also determined.

RESULTS

The liposomal formulation of ACCF had a steady characteristic absorption band at 201 nm and a transmittance of 99.20 ± 0.10%. Its average hydrodynamic particle size was 98 nm, with a PDI of 0.29 ± 0.04 and a negative zeta potential (-38.66 ± 0.33mV). TEM further confirmed the formation of vesicular, spherical nano-liposomes with unilamellar configuration. Additionally, a remarkable entrapment efficiency percent (77.58 ± 0.82%) with a permeability rate equal to 3.20 ± 0.31% and a high retention rate (54.16 ± 2.20%) for ACCF-liposomes were observed. The Fourier transform infrared spectroscopy (FTIR) result demonstrated that ACCF successfully entrapped inside liposomes. The ACCF-liposomes exhibited a slow and controlled ACCF release in vitro. Regarding stability studies, the liposomal formulation enhanced the stability of ACCF during storage and at different pH. Furthermore, ACCF-liposomes are highly stable in intestinal digestion conditions comparable to gastric digestion. The current study disclosed that liposomal formulation potentiates the biological activities of ACCF, especially antioxidant, anti-inflammatory, and thrombolytic activities.

CONCLUSION

These promising results offer a novel approach to increasing the bioaccessibility of ACCF, which may be crucial for the development of pharmaceuticals and nutraceutical-enriched functional foods.

Behavior of protein-polysaccharide conjugate-stabilized food emulsions under various destabilization conditions

The sensitivity of protein-stabilized emulsions to flocculation, coalescence, and phase separation under destabilization conditions (i.e., heating, aging, pH, ionic strength, and freeze-thawing) may limit the widespread use of proteins as effective emulsifiers. Therefore, there is a great interest in modulating and improving the technological functionality of food proteins by conjugating them with polysaccharides, through the Maillard reaction. The present review article highlights the current approaches of protein-polysaccharide conjugate formation, their interfacial properties, and the behavior of protein-polysaccharide conjugate stabilized emulsions under various destabilization conditions, including long-term storage, heating and freeze-thawing treatments, acidic conditions, high ionic strength, and oxidation. Protein-polysaccharide conjugates are capable of forming a thick and cohesive macromolecular layer around oil droplets in food emulsions and stabilizing them against flocculation and coalescence under unfavorable conditions, through steric and electrostatic repulsion. The protein-polysaccharide conjugates could be therefore industrially used to design emulsion-based functional foods with high physicochemical stability.

Parameter control, characterization and stability of soy protein emulsion prepared by microfluidic technology

A flow-focusing microfluidic device driven by pressure was employed in soy protein emulsions with uniform droplet size and good morphology. The results suggested that pressure was an essential factor for droplet formation. The optimum parameter was at a continuous phase pressure of 140 mbar and dispersed phase pressure of 80 mbar. Under this condition, the droplet formation time was shortened to 0.20 s, with average sizes of 39-43 μm and coefficient of variation of about 2 %. Emulsion stability was improved with increasing soy protein isolate (SPI) concentrations. At SPI concentrations higher than 20 mg/mL, the emulsions exhibited improved stability against changes in temperature, pH and salt concentration. Emulsions prepared in this manner exhibited superior oxidative stability than those prepared by conventional methods utilizing homogenizers. This study showed that microfluidic technology can be applied to soy protein emulsions as an effective tool for preparing droplets with uniform size and enhanced stability.

Self-assembled emulsion gel based on modified chitosan and gelatin: Anti-inflammatory and improving cellular uptake of lipid-soluble actives

To obtain a green carrier for intestinal targeted delivery, an emulsion gel was designed by the self-assembly between gelatin and Pickering emulsion based on gallic acid modified-chitosan nanoparticles (GCS NPs). The emulsion gels loaded with garlic essential oil (Geo) and curcumin (Cur) were abbreviated as GOEG and GCEG, respectively. Meanwhile, the sodium alginate bead loaded with Geo (GOEGS₃) and the bead loaded with Cur (GCEGS) were prepared as controls. Results demonstrated that the emulsion gels significantly improved the bioaccessibility of Geo and Cur, showing great intestinal targeting delivery properties comparable to that of sodium alginate beads. Moreover, Caco-2 cell experiments indicated that GOEG and GCEG displayed good biocompatibility and enhanced cellular uptake of Geo and Cur. The emulsion gels also exhibited excellent anti-inflammatory properties in the lipopolysaccharide-induced cell model, exhibiting great potential for clinical application. This work provides some references for the preparation of multifunctional emulsion gels with excellent delivery performance by a green method.

Improved physicochemical stability and bioaccessibility of astaxanthin-loaded oil-in-water emulsions by a casein-caffeic acid-glucose ternary conjugate

In this study, the influence of casein-caffeic acid-glucose ternary conjugate (CSC) on the physicochemical properties and bioaccessibility of astaxanthin-loaded emulsion was investigated and compared with sodium caseinate (CSN), a synthetic emulsifier commonly used in the food industry. The CSC-stabilized emulsion exhibits droplet characteristics similar to CSN-stabilized emulsion, and can effectively resist the external forces that lead to the phase separation of the emulsion. Although phase separation also occurred at pH 4.0, CSC emulsion had a wider range of pH stability (pH 3.0, 5.0-8.0) and higher salt ion stability than CSN emulsion. Furthermore, CSC-stabilized astaxanthin emulsions showed better astaxanthin protection under different heat treatment conditions and storage temperatures compared with CSN. After 28 days of storage at 4 °C, astaxanthin residues in the CSC-stabilized emulsion reached 92.37 %. The bioaccessibility of astaxanthin in CSC-stabilized emulsion was 26.21 %, much higher than that in CSN (6.47 %). This research study provides a platform for designing astaxanthin-fortified food or beverage systems to achieve better stability and delivery to target sites.