| Green Tea catechin epigallocatechin gallate(EGCG)has strong antioxidant and other biological activity.However,it is sensitive to light and heat,and its stability in the gastrointestinal tract after oral administration of the weak,need food grade suitable embedding carrier to enhance its stability,and to improve its oral bioavailability.This study mainly uses two kinds of water soluble chitosan derivatives chitosan hydrochloride(Chitosan hydrochloride,CHC)and carboxymethyl chitosan(Chitosan,hydrochloride,CMC)and zein protein as the carrier,embedding EGCG into negative EGCG loaded chitosan/zein(EGCG-CS/Zein)nano particles,can effectively protect the stability of EGCG,and then improve its bioavailability.The use of nanoparticles outer crosslinking of zein is hydrophobic and unique,this study also used the nanoparticles to prepare containing EGCG nano edible packaging film,in order to enhance the stability of the oil food packaging,improve packaging performance.The main contents of this paper are as follows:1.Preparation of EGCG-CS/Zein nanoparticles and determination of their properties.The factors affecting the preparation of nanoparticles were studied,including the quality of zein,the mass of EGCG,and the volume of two water-soluble chitosan(CHC and CMC)solutions.The results showed that the quality of zein was216 mg,CHC and CMC solution volume of 42 ml,EGCG 5 mg,EGCG nanoparticle size is 197.6 nm,the zeta potential was + 34.7,PDI was 0.23,the encapsulation efficiency reached 79.1%.2.Research on characterization,release and antioxidant experiments of EGCG-CS/Zein nanoparticles.The Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)show that EGCG nanoparticles are mainly composed of electrostatic interactions and hydrogen bonds in intramolecular and intermolecular interactions.Transmission electron microscopy(TEM)shows that compared with other types of nanoparticles,EGCG-CS/Zein nanoparticles are spherical particles with relatively smooth surfaces.The release profile of EGCG showed a burst effect followed by slow release.EGCG release(32%)was relatively higher from EGCG-CS/Zein nanoparticles with higher DPPH scavenging activity than that of NPs without Zein coating in 95% ethanol fatty simulant.These results indicate that controlled-release of EGCG from EGCG-CS/Zein nanoparticles and its correspondingantioxidant activities in 95% ethanol fatty simulant may provide long-term protection against oxidation for fatty foods.3.Preparation of antioxidant edible film with chitosan hydrochloride(CHC),glycerol and nanopartical suspension.The factors influencing the preparation of edible film,the amount of CHC and glycerol,and the film forming temperature were systematically studied.The optimized nanoparticles edible film was prepared by different factors.After determining the amount of glycerol and the film forming temperature,the ratio of Zein in the nanoparticles and the ratio of the added CHC were studied.The films with chitosan/Zein mass ratios of 5:1,9:1 and 12:1were optimized.4.The structural characterization of edible nano packaging films,the release rules of EGCG from membranes and their antioxidant properties were investigated.The result showed that the edible film containing nanoparticles had better mechanical properties than the control film.Compared with the control film,the edible film containing nanoparticles value of △E increased,and the color became darker and the light transmittance decreased.The intermolecular interactions between the films were illustrated by Fourier transform infrared spectroscopy and X-ray diffraction.EGCG was rapidly released into food simulant although the concentration fluctuates over time.The prepared film can effectively prevent the oxidation of fatty foods. |
