Characteristics and structure of a soy protein isolate-lutein nanocomplex produced via high-pressure homogenization

High-pressure microfluidization enhanced the stability of sodium caseinate-EGCG complex-stabilized fish oil emulsion

Improving the emulsion-stabilizing effect of protein by chemical or physical modification has been paid much attention recently. Here, sodium caseinate (CS) was treated by high-pressure-microfluidization (HPM) under 0-100 MPa, and was further complexed with (-)-epigallocatechin-3-gallate (EGCG) to form an excellent emulsifier that stabilized fish oil emulsions. Results showed that HPM treatment (especially 80 MPa) significantly changed the secondary structure of CS, and 80 MPa-PCS-EGCG had the best emulsifying and antioxidant activities. In addition, after HPM treatment and EGCG bonding, CS formed a thicker interface layer on the surface of oil droplets, which could better protect the fish oil from the influence by oxygen, temperature and ion concentration. Moreover, the fish oil emulsion stabilized by PCS-EGCG complex significantly delayed the release of free fatty acids subjected to in vitro digestion. Conclusively, HPM-treated CS-EGCG complex could be a potential emulsifier to improve the stability of fish oil emulsions.

Enhancing vitamin D3 bioaccessibility: Unveiling hydrophobic interactions in soybean protein isolate and vitamin D3 binding via an infant in vitro digestion model

In the domain of infant nutrition, optimizing the absorption of crucial nutrients such as vitamin D3 (VD3) is paramount. This study harnessed dynamic-high-pressure microfluidization (DHPM) on soybean protein isolate (SPI) to engineer SPI-VD3 nanoparticles for fortifying yogurt. Characterized by notable binding affinity (Ka = 0.166 × 105 L·mol-1) at 80 MPa and significant surface hydrophobicity (H0 = 3494), these nanoparticles demonstrated promising attributes through molecular simulations. During simulated infant digestion, the 80 MPa DHPM-treated nanoparticles showcased an impressive 74.4% VD3 bioaccessibility, delineating the pivotal roles of hydrophobicity, bioaccessibility, and micellization dynamics. Noteworthy was their traversal through the gastrointestinal tract, illuminating bile salts' crucial function in facilitating VD3 re-encapsulation, thereby mitigating crystallization and augmenting absorption. Moreover, DHPM treatment imparted enhancements in nanoparticle integrity and hydrophobic properties, consequently amplifying VD3 bioavailability. This investigation underscores the potential of SPI-VD3 nanoparticles in bolstering VD3 absorption, thereby furnishing invaluable insights for tailored infant nutrition formulations.

Extraction, identification and application of gliadin from gluten: Impact of pH on physicochemical properties of unloaded- and lutein-loaded gliadin nanoparticles

In the present study, high purity gliadin was extracted from gluten by the marginally modified Osborne method and the effect of different pHs in the aqueous ethanol on the physicochemical properties of unloaded gliadin nanoparticles (UGNs) and lutein-loaded gliadin nanoparticles (LGNs) was investigated. The results revealed that the formation of UGNs and LGNs at diverse pHs was driven by a conjunction of hydrogen bonding, electrostatic interactions and hydrophobic effects, but their dominant roles varied at different pHs. pH also significantly impacted the surface hydrophobicity, secondary structure and aromatic amino acid microenvironment of UGNs and LGNs. LGNs at pH 5.0 and at pH 9.0 exhibited better loading capacity and could reach 9.7884 ± 0.0006 % and 9.7360 ± 0.0017 %, respectively. These two samples also had greater photostability and thermal stability. Half-lives of LGNs at pH 5.0 were 2.185 h and 54.579 h, respectively. Half-lives of LGNs at pH 9.0 were 2.937 h and 49.159 h, respectively. LGNs at pH 5.0 and LGNs at pH 9.0 also had higher bioaccessibility of lutein, with 15.98 ± 0.04 % and 15.27 ± 0.03 %, respectively. These findings yielded precious inspirations for designing innovative lutein delivery system.

Improvement of delivery properties of soybean 7S protein by high-pressure homogenization: In the case of curcumin

In this study, curcumin@high-pressure homogenization-soybean 7S protein/nanoparticles (CUR@HPH-7S-NPs) were prepared by an anti-solvent method. The physicochemical properties results showed at a CUR concentration of 4 mg/mL, CUR@HPH-7S-NPs had better size, encapsulation efficiency (EE), and zeta-potential values of 151.9 nm, 88.80 %, and -23.1 mV, respectively. Fourier transforms infrared (FTIR) and endogenous fluorescence spectroscopy results indicated CUR bound to HPH-7S through hydrophobic interactions, and the force between HPH-7S and CUR molecules was greater than that between untreated 7S protein and CUR. Furthermore, the pH stability results showed the size of CUR@HPH-7S-NPs was barely affected by pH away from adjacent area of the isoelectric point of 7S protein. The physical thermal stability and bio-accessibility results suggested that HPH-7S was more effective in delaying the degradation, had more physical thermal stability, and had a significant improvement in the bio-accessibility of CUR than that of untreated 7S protein. What's more, the antioxidant activity results showed at a CUR equivalent concentration of 40 μg/mL, the DPPH and ABTS radical scavenging activity of CUR@HPH-7S-NPs was 85.10 % and 96.64 %, respectively, both of which were significantly higher than that of free CUR. Finally, this study aimed to provide a theoretical basis for the delivery of other hydrophobic bioactive substances.

Structural changes and calcium bioaccessibility of calcium fortified milk containing CaCO3 loaded solid-in-oil-in-water emulsion during simulated in vitro digestion

BACKGROUND

In most regions around the globe, average dietary calcium intake is relatively low. Consumers increasingly supplement calcium with milk. However, commercial high-calcium milk has the problem of low calcium bioaccessibility. This study was to explore calcium fortified milk containing calcium carbonate (CaCO3 ) loaded solid-in-oil-in-water emulsion as a potential novel calcium fortified milk with higher calcium bioaccessibility.

RESULTS

The CaCO3 loaded solid-in-oil-in-water (S/O/W) emulsion with good physical stability (zeta potential -33.34 ± 0.96 mV, mean particle size 4.49 ± 0.02 μm) and high calcium bioaccessibility (32.34%) was prepared when the concentration of xanthan gum was 4 g L-1 . Furthermore, the physicochemical properties and gastrointestinal fate of calcium fortified milk (calcium contents, 1.25 mg mL-1 , 1.35 mg mL-1 , and 1.45 mg mL-1 ) with different proportions of CaCO3 loaded S/O/W emulsion and pure milk were investigated. The calcium fortified milk (calcium content, 1.25 mg mL-1 ) with a small amount of CaCO3 loaded S/O/W emulsion did not significantly affect the physicochemical properties of pure milk and had similar rheological properties and higher calcium bioaccessibility to commercial high-calcium milk. Excessive calcium ion (Ca2+ ) weakens the electrostatic interaction of milk sample system and causes aggregation of colloidal particles, which was attributed to more insoluble calcium soap formation.

CONCLUSION

This study showed that the S/O/W emulsion delivery system improved the dispersion stability and bioaccessibility of CaCO3 . These findings contribute to the development of calcium fortified milk with improved physicochemical properties and higher calcium bioaccessibility. © 2023 Society of Chemical Industry.

Enhanced encapsulation of lutein using soy protein isolate nanoparticles prepared by pulsed electric field and pH shifting treatment

In this study, soy protein isolate (SPI) was modified by a pulsed electric field (PEF) combined with pH shifting treatment (10 kV/cm, pH 11) to prepare SPI nanoparticles (PSPI11) for efficient loading of lutein. The results showed that when the mass ratio of SPI to lutein was 25:1, the encapsulation efficiency of lutein in PSPI11 increased from 54% to 77%, and the loading capacity increased by 41% compared to the original SPI. The formed SPI-lutein composite nanoparticles (PSPI11-LUTNPs) had smaller, more homogeneous sizes and larger negative charges than SPI7-LUTNPs. The combined treatment favored the unfolding of the SPI structure and could expose its interior hydrophobic groups to bind with lutein. Nanocomplexation with SPIs significantly improved the solubility and stability of lutein, with PSPI11 showing the greatest improvement. As a result, PEF combined with pH shifting pretreatment is an effective method for developing SPI nanoparticles loaded and protected with lutein.