Imaging metabolic mechanisms and the binding behavior of nutrients/transporters of edible Matricaria flowers VOCs.

To promote the consumption of flowers and to utilize the nutritional value of proteins, the efficacy of the beneficial components of flowers has been intensively studied. Anthemis nobilis was used as the study object, and all its volatile components (VOCs) were fingerprinted using headspace solid-phase micro-extraction gas-mass spectrometry (HS-SPME/GC-MS). GC-MS fingerprints of five parts of Anthemis nobilis were established using three proteins, bovine lactoferrin (BLF), bovine lactoglobulin (ß-Lg), and human serum albumin (HSA), as nutrient transporters. The interactions between the volatile components from different parts of the mother chrysanthemum plant and the nutrient/transport proteins were investigated. The results of fingerprinting showed that the flavor components were dominated by alkenes. In addition, this study revealed that among the three nutrient transporters, the strongest binding to the adsorbed volatile components was HSA, followed by BLF, and ß-Lg was second. In addition, a characteristic molecule, camphene, was screened. Integrated molecular simulation using fluorescence spectroscopy was used to validate the results of the interaction of the nutrient/transport proteins systems with characteristic molecule. The properties of the characteristic molecules such as absorption, distribution, metabolism, excretion and toxicity in vivo were analyzed using ADMET to provide a theoretical basis for the preparation of flower-flavored dairy products.

Highly catalytic supramolecular host-guest complex for high value directional conversion of lignin to syringyl monomer.

In order to meet the challenge of enzyme catalysis of waste lignin, laccase (LAC)- guaiacyl(G)-type monomers noncovalent supramolecular system (LGS) were constructed for conversion of lignin. In this contribution, the catalytic effect of LGS formed by LAC and G-type monomers was studied. LAC changes the secondary structure conformation of its binding site to accommodate the G-type monomer, which is bound by hydrogen bonding and hydrophobic interactions. A mechanistic study highlights that the non-covalent complexation accelerates the internal electron transfer rate of LGS and syringol substrate for subsequent coupling reactions. In the presence of guaiacol/4-ethylguaiacol/vanillin-LAC, the conversion of dealkali lignin were 16.44, 29.12 and 22.72, respectively, higher than that in the presence of LAC alone. And the product of syringyl monomer was significantly increased in the actual lignin catalysis. Our work explains the mechanisms underlying existing enzyme-substrate interactions and enhanced catalytic system can be used for efficient utilization of waste.

Imaging human serum albumin behavior in process of PVOCs transportation in vivo: Spectroscopy analysis insight.

Pomelo volatile organic compounds (PVOCs) are used as food additives to provide unique flavors, thus, and the possible effects of VOC binding to albumin should be considered. Headspace solid-phase microextraction with gas chromatography-mass spectrometry was used to fingerprints adsorption of PVOCs on human serum albumin (HSA). Spectral data and molecular modeling were used to establish a binding model between PVOCs and HSA. Twenty-one common components were identified, and dipentene, linalylacetate, and nootkatone were identified as characteristic components. Thermodynamic calculations showed that dipentene and linalylacetate bound to HSA via van der Waals forces and hydrophobic interactions, whereas nootkatone bound to HSA via van der Waals forces alone. Molecular modeling showed that the volatile components were all bound to the hydrophobic pocket of HSA site I. Our results provide a useful basis for quality evaluation of pomelo and explain the mechanism of interaction between PVOCs and HSA.