In the present study, the formation and structure of the inclusion compound of large-ring cyclodextrin and 4-terpineol were obtained through different experiments and molecular dynamics (MD) simulation. The analysis of FTIR, 1 H-NMR, and thermodynamic results confirmed the formation of clathrates. Analysis of molecular structure (root-mean-square deviation and radius of gyration), solubility, and interaction energy (Coul, H bond) based on MD simulations further clarified the nature of the clathrate and the conformational changes caused by guest molecules as well as inclusion complexes process trends. The inclusion complex reportedly has a new crystal structure with improved thermal stability. Practical Application This is the first work to demonstrate the complex formation between 4-terpineol and large-ring cyclodextrin by molecular dynamics simulation. Molecular dynamics simulation confirmed the formation of inclusion complexes theoretically. Conformational changes of the molecules and the formation of complexes with improved thermal stability were observed. Complexing with large-ring cyclodextrin can be used as an effective means to encapsulate the aroma/flavor compounds.
Antibacterial active packaging enables extensive biological effects to improve food safety. However, it still remains difficult to achieve controlled and precise release of bioactive compounds to the specific target location with required quantity in food packaging applications. Here, a novel relative humidity (RH) - responsive polyvinyl alcohol/chitosan (PVA/CS) composite nanofibrous film incorporated with 4-terpineol/β-cyclodextrin inclusion complexes (4-TA@β-CD ICs) was engineered by electrospinning that can be exploited as a functional packaging materials. The characterization results showed the thermal stability of the films was enhanced after the incorporation due to the hydrogen bonds between ICs and biopolymers. Besides, the 4 wt% 4-TA@β-CD ICs/PVA/CS film exhibited optimized morphology, crystallinity, mechanical properties, and water vapor permeability. The incorporation of ICs dramatically promoted the antioxidant and inhibition activity of the film especially towards Shewanella putrefaciens . Moreover, the release behavior of 4-TA indicated that high RH accelerated the releasing rate, and the film obtained a sustained-release effect. Finally, the film with long-term antibacterial effectiveness succeeded in extending the shelf life of Litopenaeus vannamei shrimps by an additional 2 days at 4°C. This work developed a RH-responsive release packaging material, which may serve as an effective active food packaging.
Yajian Wu,Runhu Xin,Miao Liang,Zhimin Zhang,Wei Guan,Rui Wang,Yuping Liu
To characterize the key odorants in Amomum tsao-ko (AT) and to investigate their changes during natural drying, volatile compounds of AT were extracted and analyzed by solvent extraction combined with solvent-assisted flavor evaporation and gas chromatography mass spectrometry–olfactometry. A total of 41 aroma-active compounds with flavor dilution factors ranging from 3 to 6561 were identified in AT. Fourteen odorants were determined to be the key odorants by quantitation analyses, odor activity value (OAV) calculations, recombination and omission experiments. To further investigate the changes in aroma components in AT during natural drying, the concentrations and OAVs of odor-active compounds were measured at 0, 2, 4, 6, 8, 12, 16, and 20 days. The results showed that the number of aroma-active components did not change during natural drying, but their content changed with different trends. The concentration of geraniol showed a continuous upward trend; those of hexanal , octanal , nonanal and pinocarvone decreased first and then increased; those of α -pinene, sabinene , 2-nonanone, ( E )− 2-octenal, 2-nonanol, 4-terpineol, epidolichodial and ( E , E )− 2,4-dodecadienal changed on a fluctuating trend, while those of the other 28 compounds showed a trend of first increasing and then decreasing. These results provide a theoretical basis for further utilization of AT.