The inclusion complexes between daidzein and three cyclodextrins (CDs), namely β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Me-β-CD, DS = 12.5) and (2-hydroxy)propyl-β-cyclodextrin (HP-β-CD, DS = 4.2) were prepared. The effects of the inclusion behavior of daidzein with three kinds of cyclodextrins were investigated in both solution and solid state by methods of phase-solubility, XRD, DSC, SEM, ¹H-NMR and 2D ROESY methods. Furthermore, the antioxidant activities of daidzein and daidzein-CDs inclusion complexes were determined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) method. The results showed that daidzein formed a 1:1 stoichiometric inclusion complex with β-CD, Me-β-CD and HP-β-CD. The results also showed that the solubility of daidzein was improved after encapsulating by CDs. ¹H-NMR and 2D ROESY analyses show that the B ring of daidzein was the part of the molecule that was most likely inserted into the cavity of CDs, thus forming an inclusion complex. Antioxidant activity studies showed that the antioxidant performance of the inclusion complexes was enhanced in comparison to the native daidzein. It could be a potentially promising way to develop a new formulation of daidzein for herbal medicine or healthcare products.

Microbial contamination poses a great threat to people's life and health. In this paper, p-hydroxybenzoic acid (PHBA) was intercalated into layered double hydroxides (LDHs, with Zn : Al molar ratio = 4 : 1); the former possesses the antifungal effect for Candida albicans, and the latter shows the best antibacterial effect for Staphylococcus aureus. The sample was characterized by XRD, FT-IR spectroscopy and TG-DTA. Its sustained-release property was studied by a release experiment. Finally, ZnAl-PHBA-LDH (Zn : Al = 4 : 1) was dispersed into the solution of gelatin to obtain a food packaging film; antimicrobial experiments showed that the gelatin film of ZnAl-PHBA-LDH (Zn : Al = 4 : 1) (ZPL4) could effectively inhibit the activity of Staphylococcus aureus and Candida albicans. The experimental results confirm the application of ZPL4 in the field of food antimicrobial packaging.

In the present work, the two-phase mixture (HTLc) of hydrotalcite and its oxide were used to improve the barrier properties, UV resistance and antimicrobial activity of Poly(ethylene terephthalate) (PET) for their application in liquid milk packaging. Firstly, CaZnAl-CO₃-LDHs with a two-dimensional layered structure were synthesized by hydrothermal method. CaZnAl-CO₃-LDHs precursors were characterized by XRD, TEM, ICP and dynamic light scattering. A series of PET/HTLc composite films were then prepared, characterized by XRD, FTIR and SEM, and a possible mechanism of the composite films with hydrotalcite was proposed. Barrier properties to water vapor and oxygen have been studied in PET nanocomposites, as well as their antibacterial efficacy by the colony technique and their mechanical properties after exposure to UV irradiation for 24 h. By the presence of 1.5 wt% HTLc in the PET composite film, the oxygen transmission rate (OTR) was reduced by 95.27%, the water vapor transmission rate was reduced by 72.58% and the inhibition against Staphylococcus aureus and Escherichia coli was 83.19% and 52.75%. Moreover, a simulation of the migration process in dairy products was used to prove the relative safety. This research first proposes a safe technique for fabricating hydrotalcite-based polymer composites with a high gas barrier, UV resistance and effective antibacterial activity.

>99% antimicrobial efficiency is achieved against S. aureus, E. coli, and A. brasiliensis via Ag@NiZnAl-LDH. Low ion migration ensures safety for dairy packaging. A scalable LDPE nanocomposite achieves >81% inhibition with industrial compatibility.