The Research On The Construction And Characteristics Of Astaxanthin Complex Nanoparticles Based On Coixin

Prolamin can self-assemble in a highly polar solvent and encapsulated the hydrophobic active substance into the hydrophobic core.Coixin is the protein with the highest content in storage protein of coix seed.Astaxanthin(Astaxanthin,ASX)is a carotenoid oxygen-containing derivative.ASX has attracted increasing attention from the scientists in the fields of cosmetics,food and medicine because of its superior anti-oxidation,anti-inflammatory and other biological activities.However,the poor stability and low bioavailability of ASX limit its application.In this paper,the interaction between the coixin and astaxanthin was investigated,and then the astaxanthin delivery system based on the coixin was constructed.In addition,the stability,structural characteristics,antioxidant activities and in vitro simulated digestion characteristics of coixin based nanoparticle were studied.The main results are as follows:The interaction mechanism between coixin and astaxanthin was analyzed by fluorescence spectroscopy.There was a fluorescence quenching phenomenon between astaxanthin and coixin,and it was static and dynamic binding quenching.The binding constants of the two at 298 K and 310 K were 5988.25 and 7854.16 L/mol,respectively,and the number of binding sites was 1.507 and 1.5178 respectively.Electrostatic interaction and hydrophobic interaction may be the main driving force for the interaction between astaxanthin and coixin.Coixin-Astaxanthin-Nanoparticles(C-ASX-NP)were prepared by anti-solvent precipitation method,and the optimal preparation conditions were pH 3.5,the concentration of coixin was 3%,the concentration of astaxanthin was 0.15 mg/mL.At this time,the average particle size of C-ASX-NP is 121 nm,the ζ-potential was 39 mV,and the encapsulation efficiency and loading capacity of Astaxanthin were 49.18%and 2.45 mg/g,respectively.Using arabic gum as a stabilizer,Coixin-Astaxanthin-Arabic gum-Nanoparticle(C-ASX-AG-NP)was constructed.When the ratio of coixin to arabic gum was 1:1,the average particle size of C-ASX-AG-NP is the smallest,which is 163.43nm,the PDI is 0.123,and the encapsulation efficiency of astaxanthin is 55.07%.By comparing the stability of C-ASX-NP and C-ASX-AG-NP,it was found that the addition of gum arabic can not only enhanced the prolamin-based astaxanthin nanoparticles at pH 6、pH 7 and he stability in the environment of 12.5～37.5 mmol/L NaCl but also increased the retention rate of astaxanthin during storage.However,the stability of C-ASX-NP at 70℃was better than that of C-ASX-AG-NP.Analyzed by Fourier Infrared Spectroscopy that there were hydrogen bonds and electrostatic attraction between coixin and arabic gum.Electrostatic attraction and hydrophobic interaction were;the main driving forces for the interaction between coixin and astaxanthin,and through X-rays Diffraction verified this conclusion,and finally astaxanthin was encapsulated in the hydrophobic inner core of coixin in an amorphous form.The self-assembly of coixin and the addition of astaxanthin reduce the α-helical structure of coixin.The antioxidant activity and digestive properties of C-ASX-NP and C-ASX-AG-NP were researched.The scavenging ability of C-ASX-AG-NP on DPPH·scavenging rate and ABTS+.scavenging rate is higher than that of C-ASX-NP and higher than free astaxanthin,It was indicated that the use of coixin encapsulated astaxanthin can increase the astaxanthin antioxidant activity.In the in vitro simulated digestion experiment,the bioavailability of astaxanthin in C-ASX-NP and C-ASX-AG-NP was 11 times and 10 times that of free astaxanthin,which indicates that the prolamin-based the encapsulated system can significantly increase the utilization rate of astaxanthin.