| Resveratrol,curcumin and quercetin as polyphenolic compounds have multiple benefits,such as antioxidant,cardiovascular protection and reducing heart disease risk and preventing neurodegenerative diseases.However,the application of them is limited due to the instability and low bioavailability.Therefore,it is quite important to construct delivery systems for encapsulation and protection of polyphenols.Protein-based delivery systems could protect and deliver bioactive substances effectively.Therefore,this paper constructed three different delivery systems and studied the mechanism of interaction between bioactive polyphenols and proteins.Firstly,the construction and binding mechanism of lactoglobulin-based milk protein and polyphenol delivery system were studied.Secondly,the construction and binding mechanism of pea protein and polyphenol delivery system were studied.The third is the construction and characterization of mixed animal and plant protein and polyphenol delivery system.This paper provides a new idea for improving the environmental stability and bioavailability of lipophilic polyphenols,and provides a strong support for the in-depth research and wide application of polyphenols delivery system.The research contents and results of this paper are as follows:(1)Fluorescence spectroscopy and molecular docking confirmed that curcumin,resveratrol and lactoglobulin were combined by hydrogen bonding,van der Waals force and hydrophobic force.Fluorescence quenching spectroscopy and time-resolved spectroscopy were used to determine that the quenching mechanism of curcumin and resveratrol with lactoglobulin.The binding mechanism between polyphenols and lactoglobulin was static quenching.The prepared nanocomplexes had strong electronegativity and high physical stability.Differential scanning calorimetry and X-ray diffraction experiments indicated that curcumin and resveratrol were successfully encapsuled in lactoglobulin and transformed from crystalline to amorphous state.The milk protein delivery system enhanced the UV radiation protection of curcumin resveratrol and improved the antioxidant activity of the bioactive substance.(2)Fluorescence experiments indicated the binding mechanism between polyphenols and pea protein.And fluorescence thermodynamics experiments verified that the main driving force between pea protein and curcumin and resveratrol was hydrophobic force,and the main driving force between pea protein and quercetin was hydrogen bond force.Fourier infrared experiments and molecular docking experiments indicated that hydrophobic force,hydrogen bond and van der waals force were intermolecular binding forces.The complexes with a particle size of 150-160 nm were constructed,and the zeta potential of all samples were about-28 mv.The electrostatic repulsion was relatively large which showed the delivery system had certain physical stability.The loading efficiency of three polyphenols in pea protein was determined.And the loading efficiency of resveratrol was the highest.Finally,the delivery system was evaluated by the photothermal stability and antioxidant activity before and after polyphenol encapsulation.It was found that the photothermal stability and ABTS and DPPH antioxidant activities of curcumin and resveratrol after encapsulation were significantly improved.(3)The water holding capacity and texture analysis experiments,showed that the morphology of emulsion gel prepared by different proportions of pea protein and whey protein was quite different.The hardness,chewiness and water holding capacity of emulsion gel prepared with different protein ratios were also quite different.The microstructure of the emulsion gel was observed by scanning electron microscope,and it was found that the water holding capacity of the emulsion gel was higher when the calcium ion addition was 50 m M.On this basis,polyphenols were loaded.Fourier infrared spectrum of curcumin-loaded emulsion gel system confirmed that curcumin was successfully encapsuled in the emulsion gel. |
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