Study On The Construction And Stability Of Nanoemulsion Based On Whey Protein-Hesperidin Complex

The construction of nano-delivery carriers to improve the water solubility,stability and biological potency of many insoluble biologically active substances or drugs has become a hot research topic in related fields.The protein-polyphenol covalent complex delivery carrier can improve its own functional properties,which is of great significance to the development of food,beverages,dairy products,etc.or to improve nutrition.In this paper,the covalent complex formed by whey protein(WP)and hesperidin(HES)was used to study the formation mechanism and antioxidant properties of the complex,and to evaluate the physical and chemical stability of the nanoemulsion system constructed by it.The main research contents and conclusions are as follows:(1)Through multispectral and molecular docking technology,the quenching types,binding constants,thermodynamic parameters,non-radiative energy transfer,etc.of the WP-HES interaction were explored,and the influence of HES on the structure of WP was characterized at the same time.Multispectral experiments show that HES can cause fluorescence quenching of WP,and the mechanism is mainly static quenching.According to thermodynamic parameters,non-radiative energy transfer and molecular docking,it is judged that the main force between WP-HES is hydrophobic force.Synchronous fluorescence spectroscopy shows that HES can cause changes in the microenvironment of aromatic amino acids inside WP.Infrared spectroscopy showed that HES caused a change in the secondary structure of WP.According to the analysis of the amide I band,the percentages of ?-helix and ?-sheets decreased,and the percentages of ?-turns and random curls increased.(2)The antioxidant capacity of HES and WP-HES complexes was measured by three methods: DPPH?FRAP and ABTS.By comparing the changes in the antioxidant capacity of HES before and after mixing with WP,the effect of the covalent or noncovalent interaction of polyphenols and proteins on the antioxidant properties of the two complexes was reflected.The experimental results of the three methods showed that the antioxidant capacity of the protein system after adding HES showed a significant enhancement in a dose-dependent manner.However,after mixing with WP in a certain proportion,HES does not reach the best scavenging ability,and its antioxidation ability decreases.(3)Through the characterization of the particle size,potential and microstructure of the emulsion,the effect of HES on the physical stability of the coix seed oil emulsion was explored.The experimental results show that in the presence of salt ions and different p H values,adding HES to the emulsion can improve its physical stability,promote the particle size of the emulsion to become smaller,the absolute value of the potential becomes larger,and the droplets are not easy to aggregate and are relatively high.The dosage of HES can more easily improve their physical stability.Through the determination of the primary and secondary oxidation products of the emulsion,the results show that the addition of HES can inhibit the oxidation of the emulsion to a certain extent.High-dose HES is also easier to inhibit lipid and protein oxidation to enhance the antioxidant capacity of the emulsion.