Preparation Of Zein Or Corn Peptides Composite Nanoparticles And Its Delivery And Antioxidant Properties

On the demand of nutrition and health of food, a large amount of bioactive substance hasbeen widely used in all kinds of food systems. However, the water-solubility and the stabilityof the bioactive substance are limited. The nano-assembly and nano-capsulation technologycan increase the colloid stability, the biological activity, the accessibility and thebioavailability of bioactive substance, which has potential business prospects. Zein and cornpeptides are ideal carrier because of their unique self-assembly property. Induced bydesolvation method, zein or corn peptides could co-assembled with bioactive substances tocreate copolymer with nano-size, high encapsulation efficiency and colloid stability. Thechemical and celluar antioxidant activity of nano-copolymer was also investigated. The mainresults were as follows:(1) Soybean isoflavone loaded zein nanoparticles were prepared by supercritical CO2anti-solvent technology (SAS). The influence of the preparation parameters, such as thesolution concentration, pressure, temperature and the flow rate, on the colloid particles sizewas investigated. Under the condition that zein concentration was10mg·mL-1，pressure was10MPa，temperature was45℃，sample flow rate was0.6mL·min-1，CO2flow rate was20g·min-1, the size of composite particles could be controlled below200nm with encapsulationefficiency(34.98%~73.23%), through adjusting the ratio of zein and soybean isoflavone. Thecomposite particles were nano-sphere, as confirmed by dynamic light scattering (DLS) andatomic force microscope (AFM). Solid state characterization by fourier transform infrared(FTIR) and differential scanning calorimetry (DSC) indicated the hydrogen bond andhydrophobic interaction were main forces during the formation of soybean isoflavone/zeincomposite nanoparticles.(2)-tocopherol(TOC)/corn peptides composite nanoparticles were prepared bydesolvation method. The difference of colloid stability, delivery and antioxidant abilitybetween non-aqueous corn peptides and aqueous corn peptides was investigated.TOC/non-aqueous corn peptides nanoparticles had great colloid stability. It kept stable andhigh encapsulation efficience under high peptide concentration and high ionic strengh, whileTOC/aqueous corn peptides particles became larger and its encapsulation efficiency decreased sharply, as the peptide concentration above6mg·mL-1and ionic strength increasing to300mM. When pH closed to3.0, those two composite particles would gather and theencapsulation efficiency decrease greatly. Those two corn peptides both had obvious ABTSand DPPH radical scavenging capacity. However, solid state characterization by cellularantioxidant activity experiment (CAA) showed that CAA value of non-aqueous corn peptideswere greatly stronger than that of aqueous corn peptides. The non-aqueous corn peptidescould also greatly improve the CAA value of TOC, which indicated that the non-aqueous cornpeptides not only had good celluar penetrating ability but also could carry TOC into cells. Theamino acid sequence AAQVLV of599.3643mw may be the main active ingredients of cornpeptides, as confirmed by HPLC-MS technology.(3) To improve the pH stability of TOC/corn peptides nanoparticles. Cornpeptide-maltodextrin conjugates (pep-MD) were prepared by the Maillard reaction. Pep-MDconjugates co-assembled ith-tocopherol (TOC) to create composite nanoparticles bydesolvation method. The composite particles were nano-sphere, as confirmed by dynamiclight scattering (DLS) and atomic force microscope (AFM). Compared with corn peptides andcorn peptides/maltodextrin mixtures (pep/MD), TOC/pep-’ nanoparticles on’t gather andthe solution stayed transparent in the acid condition. Pep-MD conjugates also provided betterprotection and controled the release of TOC. TOC/pep-MD nanoparticles had80.80%encapsulation efficiency after freeze-dried. In the simulated gastric fluid for3h, the release ofTOC/pep-MD nanoparticles was only23.57%. The radical scavenging capacity and cellularantioxidant activity of corn peptide was reduced after the Maillard reaction but increased afterloading TOC. In a conclusion, pep-MD conjugates are ideal carrier for bioactive substance.