Fabrication Of Zein-Carboxymethyl Cellulose Nanoparticles For Co-Encapsulation Of Polyphenols

In recent years,the development of functional food containing bioactive agents has been the focus of food and nutrition researchers.As the synergistic effect of different bioactive agents has been widely reported,consumers require that multiple biologically bioactive agents with health benefits be added to functional foods simultaneously to meet personalized nutritional needs.As natural plant polyphenols,quercetin and resveratrol have good antioxidant,anti-inflammatory,anti-cancer and other physiological activities.However,quercetin and resveratrol have low bioavailability and poor chemical stability,which greatly limit their application.Co-encapsulation technology can protect and control the release of bioactive agents and achieve synergistic effect by regulating the proportion and dose of different bioactive agents.In this study,zein-carboxymethyl cellulose nanoparticles(zeinCMC)were successfully prepared by anti-solvent precipitation method using two natural biopolymers,zein and carboxymethyl cellulose(CMC).The stabilization mechanism of zeinCMC nanoparticles on quercetin and resveratrol was discussed,the stability of composite nanoparticles in different environments was systematically investigated,and the potential effect of zein-CMC nanoparticles on the release rate of quercetin and resveratrol was investigated by simulated digestion in vitro.In addition,this study also discussed the stabilization mechanism and release characteristics of polyphenols co-encapsulated by nanoparticles with different carrier forms,in order to provide reference for the design of personalized nutrition system of polyphenols.The main conclusions are as follows:1.Zein-CMC nanoparticles were prepared by anti-solvent precipitation method.The results show that when the mass ratio of zein to CMC was 2:1,the particle size of zein-CMC nanoparticles was the smallest(204.6 nm).The results of Fourier transform infrared spectroscopy show that the hydrogen bond and electrostatic interaction were involved in the formation of zein-CMC nanoparticles.The results of fluorescence spectra show that the fluorescence intensity of zein-CMC nanoparticles was significantly lower than that of single zein nanoparticles,which is due to the interaction between negatively charged CMC and tryptophan and tyrosine residues in zein.The results of contact angle show that CMC can improve the hydrophilicity of zein nanoparticles.The results of scanning electron microscope showed that the surface of zein-CMC nanoparticles with different mass ratio was smooth and the size was uniform.In addition,zein-CMC nanoparticles have good redispersion.2.Quercetin and resveratrol were co-encapsulated with the zein-CMC nanoparticles.It was found that the quercetin and resveratrol-loaded zein-carboxymethyl cellulose nanoparticles(QRZC nanoparticles)showed good entrapment efficiency and loading capacity,and the presence of CMC anionic polysaccharides improved the entrapment efficiency and loading capacity of the nanoparticles.Through the investigation of the influence of environmental factors on the stability of QRZC nanoparticles,it is found that the QRZC nanoparticles have good thermal stability and the nanoparticles will not aggregate or precipitate under the condition of p H 3.0～6.0.When the salt concentration was low,the QRZC nanoparticles remained relatively stable in the concentration range of 0 m M to 10 m M.However,when the salt concentration increased to 40 m M,the particle size increased obviously and the particles began to aggregate.This is because the electrostatic shielding effect was significantly enhanced and the electrostatic repulsion between the particles was obviously weakened with the increase of ionic strength.3.The photothermal stability of quercetin and resveratrol was significantly improved in QRZC nanoparticles.The results of antioxidant experiments showed that co-encapsulation quercetin and resveratrol in QRZC nanoparticles did not reduce their antioxidant activity,which may be related to the antioxidant capacity of zein and CMC.Under simulated gastrointestinal conditions,QRZC nanoparticles can delay the release of quercetin and resveratrol.The entrapment of CMC slowed down the digestion of QRZC nanoparticles,which has a slow release effect on quercetin and resveratrol.4.Different carrier forms of nanoparticles were constructed by layer-by-layer assembly technology(QRZC,QZRC and RZQC nanoparticles).It is found that these three carrier forms of particles have good particle stability.In addition,the nanoparticles prepared by layer-bylayer assembly technology have better entrapment effect on polyphenols.Hydrogen bonding,hydrophobic interaction and electrostatic interaction were involved in the formation of QRZC,QZRC and RZQC nanoparticles.Under the protection of QRZC,QZRC and RZQC nanoparticles,quercetin and resveratrol can achieve sustained release in the gastrointestinal environment.