Sodium caseinate–maltodextrin conjugate hydrolysates: Preparation, characterisation and some functional properties

Development of a Dermal Nanoemulsion with Antioxidants Derived from Rice Residues Using an HLD Theory Approach

Agricultural waste, such as rice straw, has become increasingly valuable as biocomposites in various industries. For cosmetic and pharmaceutical sectors, these biocomposites have improved active substance incorporation and waste reduction, which is pivotal for mitigating environmental impact. This study reports the encapsulation of a protein derivative derived from rice straw within a nanoemulsion for skin care applications, emphasizing stability and efficacy. Protein hydrolysates were produced by extracting proteins in an alkaline medium, followed by precipitation at the isoelectric point. The hydrolysates were enzymatically treated with Alcalase® at 80 °C and pH 10 for 45 min to generate antioxidant-rich formulations. Utilizing Hydrophilic-Lipophilic Deviation (HLD) theory, oil-in-water (O/W) emulsions were formulated by adjusting variables to achieve an HLD near zero. Sunflower oil and surfactants were combined, stirred at 70 °C, and homogenized using a rotor-stator. The final formulation's stability and permeability were evaluated through fluorescence microscopy, particle size analysis, zeta potential measurements, and accelerated stability assays. Nanoemulsion ENE37 showed high stability with 47.25 nm size, PDI 0.21, and excellent dispersion, maintaining integrity without phase separation. Hydrolyzed protein into ENE37 (NE37-HP) improved stability, increasing zeta potential and preventing aggregation while maintaining structure without phase inversion. NE37-HP exhibited shear-thinning behavior and good diffusion capacity, achieving 20.14 μg/cm2.h. The HLD theory and ternary diagrams are valuable methodological tools for formulating stable nanoscale emulsions. Additionally, this dosage form, containing protein hydrolysates derived from rice straw, demonstrated potential for adequate dermal absorption in humans.

Physicochemical characterization and environmental stability of a curcumin-loaded Pickering nanoemulsion using a pea protein isolate-dextran conjugate via the Maillard reaction

This study investigated pea protein isolate (PPI) and dextran (DX) conjugates produced via the Maillard reaction as Pickering stabilizers for various food applications. The results found that as heating time increased (0-5 h), the grafting degree heightened. The PPI-DX conjugate exhibited a rough porous surface in contrast to native PPI, accompanied by changes in molecular weight and secondary structure. Additionally, the aggregation of low-solubility PPI was partially inhibited due to the contribution of increased solubility and reduced surface hydrophobicity by glycation. Curcumin-loaded Pickering nanoemulsions stabilized with PPI-DX had smaller droplets and higher curcumin encapsulation (greater than80 %) than PPI-stabilized nanoemulsions. PPI-DX adsorbed on the interface showed improved physical stability compared to PPI alone, even after various pH conditions and three heat treatments. The nanoemulsion stabilized with PPI-DX demonstrated improved apparent viscosity and dispersion stability. These findings highlight the effectiveness of PPI-DX conjugates as stabilizers for developing stable and functional Pickering nanoemulsions.

Performance of rice protein hydrolysates as a stabilizing agent on oil-in-water emulsions

Rice protein isolate (RPI) has been receiving increasing attention from the food industry due to its performance as an emulsifier. However, it is possible to enlarge its field of applications through enzymatic hydrolysis. Therefore, this work aimed to investigate the effects of the controlled enzymatic hydrolysis (degree of hydrolysis DH as 2, 6, and 10%) using Flavourzyme on the physicochemical properties of rice protein and to identify the minimum concentration of these hydrolysates (0.5, 1.0, and 1.5%) to form and stabilize oil/water emulsion. The physicochemical, interfacial tension (IT), and surface characteristics of RPI and their hydrolysates (RPH) were determined. Even at a lower protein concentration (1.0%), protein hydrolysate presented lower IT when compared with RPI at a higher protein concentration (1.5%). The interfacial tension decreased from 17.6 mN/m to 9.9 mN/m when RPI was hydrolyzed. Moreover, enzymatic hydrolysis (DH 6 and 10%) enhanced the protein solubility by almost 20% over a pH range of 3-11. The improved amphiphilic property of RPH, supported by the results of IT and solubility, was confirmed by the higher emulsion stability indicated by the Turbiscan and emulsion stability indexes. Emulsions stabilized by RPH (DH 6% and 10%) at lower protein concentrations (1%) exhibited better physical stability than RPI at higher protein concentrations (1.5%). In this work, we verified the minimum concentration of rice protein hydrolysate required to form and stabilize oil-in-water (O/W) emulsions.

Enzymatically hydrolyzed sodium caseinate nanoparticles efficiently enhancing the solubility, stability, and antioxidant and anti-biofilm activities of hydrophobic Tanshinone IIA

Enzymatic hydrolysis has been validated as an appropriate strategy for improving the properties of natural protein. Here, we used enzymatic hydrolysis sodium caseinate (Eh NaCas) as a nano-carrier for enhancing the solubility, stability, and antioxidant and anti-biofilm activities of hydrophobic encapsulants. Tanshinone IIA (TA) was loaded into the hydrophobic regions of Eh NaCas by self-assembly, and the encapsulation efficiency could reach 96.54 ± 0.14% under an optimized host-guest ratio. After Eh NaCas packed, the TA-loaded Eh NaCas nanoparticles (Eh NaCas@TA) showed regular spheres, uniform particle size distribution and more optimal drug release. Moreover, the solubility of TA in aqueous solution increased over 2.4 × 10⁵ times, and the TA guest molecules displayed excellent stability under light and other harsh environments. Interestingly, the vehicle protein and TA exhibited synergistic antioxidant effects. Furthermore, Eh NaCas@TA forcefully restrained the growth and destroyed the biofilm construction of Streptococcus mutans compared to free TA, showing positive antibacterial activity. The establishment of these results demonstrated the feasibility and functionality of edible protein hydrolysates as nano-carriers for loading natural plant hydrophobic extracts.

Structure of whey protein hydrolysate used as emulsifier in wet and dried oil delivery systems: Effect of pH and drying processing

The secondary structure of whey protein concentrate hydrolysate (WPCH), used as an emulsifier in oil delivery systems, was investigated using Synchrotron Radiation Circular Dichroism (SRCD). The effect of pH on the conformation of peptides in solution and adsorbed at the oil/water interface, as well as the thermal stability of the systems was studied. Furthermore, oil-loaded microcapsules were produced by spray-drying or electrospraying to investigate the influence of encapsulating agents (glucose syrup, maltodextrin) and drying technique on the secondary structure of WPCH at the oil/water interface. Enzymatic hydrolysis resulted in peptides with a highly unordered structure (∼60% turns and unordered regions) in solution. However, WPCH adsorption onto the oil/water interface increased the α-helical content resulting in an improved thermal stability. The encapsulating agents and spray-drying process did not modify the conformation of WPCH at the oil/water interface. Nonetheless, electrospraying affected the SRCD spectra obtained for WPCH adsorbed at the oil/water interface.

The effect of soy protein structural modification on emulsion properties and oxidative stability of fish oil microcapsules

Hydrolysates of soy protein isolate-maltodextrin (SPI-Md) conjugate were used as wall material to prepare fish oil microcapsules by freeze-drying method. Effects of the protein structural modifications on the physicochemical properties of the emulsion and the oxidative stability of the microcapsules were characterized. Compared with emulsions of SPI-Md conjugates or soy protein isolate/maltodextrin (SPI/Md) mixture, lower droplet size (212.5-329.3nm) and polydispersity index (PDI) (0.091-0.193) were obtained in the fish oil emulsions prepared by SPI-Md conjugate hydrolysates. The improved amphiphilic property of SPI-Md conjugate hydrolysates was supported by the results of surface and interfacial tension, and further confirmed by the improved emulsion stability during the storage period. Although the microencapsulation efficiency (MEE) of SPI-Md conjugate hydrolysates slightly decreased from 97.84% to 91.47% with the increasing degree of hydrolysis (DH), their oxidative stabilities (peroxide value and headspace propanal) were apparently improved compared with native SPI/Md mixture or SPI-Md conjugates system. Moreover, favorable thermal stability as well as a porous and uniform surface structure of the microcapsules coated by SPI-Md conjugate hydrolysates (DH 2.9%) was observed via the thermal analysis and scanning electron microscope (SEM) micrographs, respectively.

Physicochemical properties and emulsion stabilization of rice dreg glutelin conjugated with κ-carrageenan through Maillard reaction

BACKGROUND

Rice dreg is an underutilized source of cereal protein with good potential for application in the food industry. Glutelin represents about 850 g kg(-1) of total storage protein in rice dreg. The objective of this study was to characterize the physicochemical properties and emulsion stabilization of the Maillard type conjugate formed with rice dreg glutelin (RDG) and κ-carrageenan (1:2 weight ratio) dry-heated at 60 °C and 79% relative humidity for 24 h.

RESULTS

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Fourier transform-infrared analysis provided evidence on the formation of the Maillard type conjugation. Amino acid analysis suggested that the major locus during the Maillard reaction were lysine and arginine. Circular dichroism spectra showed decreasing amounts of α-helix and β-strand in the products with increment in the amount of turns and random coil. Conjugation with κ-carrageenan could significantly improve solubility of RDG (P < 0.05). Measurements of mean droplet size and creaming stability in oil-in-water emulsions showed that the conjugate was more effective at stabilizing emulsions at low pH or in the presence of high ionic strength.

CONCLUSION

The Maillard reaction can be successfully used as a coupling method for RDG and κ-carrageenan to form the conjugate with improved solubility and emulsion stabilization.