Desirable characteristics of casein peptides with simultaneously enhanced emulsion forming ability and antioxidative capacity in O/W emulsion

Comparison of the physical stability, microstructure and protein-lipid co-oxidation of O/W emulsions stabilized by l-arginine/l-lysine-modified soy protein hydrolysate

This work investigated the physical stability, microstructure, and oxidative stability of the emulsions prepared by soy protein hydrolysate (SPH) after modification with different concentrations of l-arginine and l-lysine. l-Arginine and l-lysine significantly increased the absolute zeta potential values, and decreased droplet sizes of the emulsions, thereby improving the physical stability of the emulsions. Meanwhile, l-arginine and l-lysine markedly decreased the apparent viscosity of the emulsions. The measurement of interfacial protein adsorption percentage showed that l-arginine (≤0.5 %) promoted the adsorption of SPH at the oil-water interface, whereas l-lysine (≤1%) reduced the adsorption of SPH at the oil-water interface. In addition, l-arginine and l-lysine (≤0.5 %) could retard lipid and protein oxidation. Correlation analysis indicated that the improvement in the physical stability of the emulsions by l-arginine and l-lysine also enhanced the oxidative stability of the emulsions. In summary, l-arginine and l-lysine could be effective modifiers for the protein-based emulsion systems.

Cell Penetrability of a γ-Crystallin Peptide Fragment from the Discarded Cataractous Eye Emulsion

The efficiency of the intracellular transport of medication and target specificity is frequently hampered by biological obstacles. The potential for therapeutic use of peptide fragments from naturally occurring proteins is promising, as peptides exhibit high selectivity due to several possibilities of interaction with their target. Certain peptide sequences, often referred to as cell-penetrating peptides (CPPs), are those that can penetrate cell membranes. Our goal is to find these sequences in the discarded postcataractery surgery emulsion known as the cataractous eye protein isolate (CEPI). One peptide fragment from this discarded protein has been identified to be a potential CPP based on the similarities with other well-known CPPs. Cell membrane penetrability and cytotoxicity of the peptide have been investigated. Fibroblast cells were incubated with the fluorescently labeled peptide and were observed under fluorescence as well as under confocal microscopy. It was found that the peptide possesses a cell-penetrating ability.

Stability protection of lutein emulsions by utilizing a functional conjugate of collagen and Lycium barbarum L. leaf flavonoid

Lutein exhibits excellent functional activity making it useful in many fields. Nevertheless, its use is limited by its physical and chemical instability. Here, collagen and Lycium barbarum L. leaf flavonoids (LBLF) were used as emulsifiers, their structures were characterized, the properties of the complexes were evaluated, and their stabilizing effects on lutein emulsions were explored. According to the results, the encapsulation rate of the complex of collagen-LBLF was (68.67 ± 1.43) % and the drug loading was (6.92 ± 0.13) %. Collagen compounded LBLF with a changed structure and morphology, resulting in improved antioxidant capacity, better foaming and emulsification, and reduced hydrophobicity. In addition, the thiobarbituric acid value of collagen-LBLF stabilized lutein emulsion (0.0012 ± 0.00011) mg/kg was significantly lower than that of collagen stabilized lutein emulsion (0.0021 ± 0.00016)  mg/kg (P < 0.05), indicating that the composite stabilized lutein emulsion obtained higher stability. LBLF contributed a high free radical scavenging effect and inhibited lutein degradation during storage. During simulated digestion, collagen-LBLF effectively stabilized the emulsion and protected lutein from destruction, made it release more slowly, and benefited the bio-accessibility of lutein during the next utilization step. Based on the present study, improved storage and digestion stabilities of lutein wereachievedby the utilization of collagen-LBLF complex, which provides a new method for the preparation and application of composite functional emulsifiers.

Effects of enzymatic modification on the stability of cashew-based milk

The green and low-carbon awareness drives the consumption demand for "clean-label" plant-based milk, which is limited by its physicochemical stability. Herein, the effects of enzymatic hydrolysis on the stability of cashew-based milk (CM) are explored in detail. Our results showed that a maximum protein solubility of 41.36 ± 2.14% was achieved under bromelain treatment of CM either for 60 min or with the addition of 600 U g-1. Under these hydrolysis conditions, CM showed smaller particle size, larger zeta potential, and more uniform size distribution in comparison with the control. Similar behavior was also observed in the apparent viscosity and macroscopic stability, demonstrating the fortification of moderate hydrolysis on the physical stability of CM. Interestingly, bromelain hydrolysis could favor improving the oxidative stability of CM, for which the peroxide value and thiobarbituric acid reactive substances were decreased by 90% and 60%, respectively, after 14 days of storage in comparison with the control. The correlation analysis confirmed that the physical and oxidative stability was highly associated with protein solubility and secondary structures like α-helix. Therefore, our findings could provide scientific support for developing plant-based milk with fortified physicochemical stability.