Fabrication And Mechanism Of Curcumin And Myosin Self-assembled Nanocomplex

With the aging population,ecological environment and lifestyle changes,the demand for functional food continues to grow and develop rapidly in the world.Effective transport and stabilization of functional factors is the key to ensure the function of functional food to promote health and regulate human body function.Nanotechnology is an effective way to promote the dissolution and increase the efficiency of bioactive substances.Protein is widely used as the carrier of food-grade bioactive substances due to its recognized safety and biocompatibility.However,most of the researches focus on plant protein and dairy protein,while the literature on the meat proteins as carriers for polyphenols is considerably rare.Myosin is the protein with the highest content and the most important in muscle.In theory,myosin is a more suitable encapsulating material than other proteins mainly because they contain all dietary essential amino acids,particularly those with high digestibility.Therefore,in this study,myosin was used as carrier to encapsulate curcumin to explore the fabrication of nanocomplex and its potential strategy to improve the oxidative stability of marinated meat products.In addition,the mechanism of myosin aggregation induced by curcumin and the mechanism of interaction between curcumin and myosin were systematically investigated.This work laid the foundation for the complex construction of curcumin and myofibrillar protein and other meat proteins,with a view to improving the oxidative stability of preserved meat products.The main conclusions are as follows:1、Fabrication of curcumin-myosin nanocomplex and its oxidative stability on marinated meatA novel nanocomplex based on myosin embedded curcumin was investigated as a potential strategy to improve the oxidative stability of marinated meat products.Myosin has a strong ability to encapsulate curcumin,and the presence of myosin significantly improves the antioxidant,storage,heat and light stability of curcumin,which is beneficial for industrial applications.At fixed protein concentration,curcumin-myosin dispersion at low concentration of curcumin（40-80 μg/mL）exhibited strong stability with the encapsulation efficiencies of the nanoparticles above 80%,whereas excessive curcumin concentration led to the formation of large myosin aggregates.In addition,the oxidative stability experiments of marinated chicken breast products showed that the curcumin-myosin complex solution could effectively inhibit the oxidation degree of fat and protein,and improve its oxidative stability.2、Molecular dynamics simulation exploration of the mechanism of myosin aggregation induced by curcuminThis study aimed to reveal the mechanism of myosin aggregation induced by curcumin.Molecular dynamics studies showed that high concentration of curcumin could induce myosin aggregation under certain protein concentration conditions,and curcumin self-association was the main reason for inducing protein aggregation.Curcumin formed molecular stacks by hydrophobic interaction,followed by hydrogen bond to further enhance the interaction among small molecules.Then,the curcumin group bridged the protein chains on both sides through hydrophobic interaction and hydrogen bond,further inducing the proteins on the two sides of curcumin group to move increasingly closer.The myosin entangled with one another to further interact,resulting in the formation of larger aggregates.3、Molecular dynamics simulation exploration of the interaction between curcumin and myosin combined with the results of spectroscopy techniquesThis study aimed to reveal the interaction of curcumin with myosin and explore the potential of this meat protein as delivery system for curcumin.The curcumin/myosin complex was confirmed by UV-Vis spectroscopy,and fluorescence spectra suggested a static quenching in the binding with strong affinity of 1.5 ×105 M-1.CD studies indicated that the interaction between curcumin and myosin caused slight changes in the secondary structure of the protein,which was consistent with the results of molecular dynamics observations.The phenomenon indicated that the conformational changes induced by curcumin are limited to binding sites and do not involve significant changes in protein folding.Furthermore,hydrophobic interaction and hydrogen bond were observed to promote the curcumin-myosin complexation by molecular dynamics simulation technique.Molecular simulation results suggested that curcumin tends to combined with the residues 801-850 in the head region of protein,1156-1195,and 1739-1743 of A chain,1162-1218,and 1736-1745 of B chain in the tail region over the course of curcumin and myosin interaction.