Dairy protein–ligand interactions upon thermal processing and targeted delivery for the design of functional foods

Effect and mechanisms of thermal sterilization methods on the in vitro phenolic bioaccessibility of rose tea with milk

Rose polyphenols, key functional components in roses, require adequate bioaccessibility for their health benefits, subject to influence by food components and processing. Investigating the impact of various thermal sterilization methods on the bioaccessibility of rose polyphenols in rose tea with milk and the underlying mechanisms, our findings indicated a significant increase in bioaccessibility following treatment at 85 °C/30 min. Conversely, 121 °C/15 min treatment decreased bioaccessibility. Examining the interaction between β-casein in milk and rose polyphenols under different sterilization conditions, SEM and particle size analysis revealed binding, with fluorescence spectroscopy indicating non-covalent bonds. Binding forces followed the order 121 °C > 85 °C > 25 °C. Notably, at 85 °C, non-covalent binding improved polyphenol bioaccessibility, while the intensified binding at 121 °C decreased it. SDS-PAGE and amino acid analysis confirmed no covalent bond. This study establishes a theoretical basis for selecting thermal sterilization temperatures for milk-flower combinations, considering polyphenol bioaccessibility.

Fabrication of colloidal stable gliadin-casein nanoparticles for the encapsulation of natamycin: Molecular interactions and antifungal application on cherry tomato

Natamycin was encapsulated in gliadin-casein nanoparticles (G-C NPs) to control black rot in cherry tomato against Alternaria alternata. The G-C NPs with a mean particle diameter of 211 ± 4 nm were prepared using an anti-solvent method. The composite NPs showed better stability against neutral pH, ion, and storage than gliadin NPs. The quenching of gliadin by natamycin was static with a constant of 5.99 × 10^-12 M^-1∙S^-1, and was spontaneous with a free energy of -23.5 kJ∙M^-1 at 298 K. Both hydrophobic stacking and hydrogen bonds between natamycin and gliadin were found as the major driven force in the formation of the complex. The NPs kept the antifungal activity of natamycin with improved photostability. The NPs coatings exhibited better results than natamycin in controlling black rot on cherry tomato. This study shows the potential of the G-C NPs as all-natural delivery systems for natamycin in post-harvest treatments.

Elucidation of interaction between serum albumin and ginsenoside CK along with cytotoxic study

As a main metabolite of ginsenosides, compound K (CK) has a vast array of pharmacological effects. However, due to its low polarity and insoluble in water, its oral application has been greatly limited. In this work, the interaction between serum albumin and ginsenoside CK was elucidated by multi-spectroscopic studies. The result of ultraviolet/visible absorption spectroscopy showed that the conformation of serum albumin could be changed via binding with CK. The result of fluorescence spectroscopy suggested that CK could form complex with serum albumin. CK could quench the fluorescence and the fluorescence residues of serum albumin were located in or near the binding position. Molecular docking indicated that CK bound at Sudlow's site II of serum albumin and formed hydrogen-bonding interactions with three residues. Furthermore, the flexible side chain of CK was difficult to be stabilized at the binding site, resulting in its serious perturbation during dynamics simulation. This work also performed the cytotoxic study and the result showed that serum albumin enhanced the inhibitory effect of CK on the proliferation of both Caco-2 and HCT-116 cells. To sum up, this work revealed that serum albumin might be an appropriate carrier of hydrophobic compounds, with the advantage of improving their biocompatibility.