Study On Microencapsulation And Preparation Of The Immunopeptide Of The Maize Yellow Powder

ObjectiveThe maize yellow powder was adopted in this experiment to produce immunopeptide and develop relevant products,for the purpose of addressing the problem of failure to utilize maize yellow powder due to poor water solubility and difficult digestion and absorption performances of its total proteins.This research provided a new approach to select raw materials for the production of protein and proposed new ideas to comprehensively make use of by-products and increase the added value of the products.MethodsFive types of enzyme,inncluding alkaline protease,neutral protease,trypsin,pepsase and compound protease were selected to produce the maize yellow powder into zymolyte.Influences of different zymolytes on the maize yellow powder peptide in terms of its immunological competence,degree of hydrolysis(DH),amino acid content and secondary structure were respectively analyzed,according to which the optimal enzyme species to extract the immunopeptide was screened.On the basis of the single factor and orthogonal experiment,the optimal technological parameters to extract immunopeptide of the maize yellow powder by enzyme were worked out.The immunopeptide of the maize yellow powder was desalinated and purified using the DA201-C macroporous adsorbent resin.Then,immunological competence of the purified immunopeptide was measured.In line with the single factor and response surface analysis,the technique conditions to produce the immunopeptide microcapsule of the maize yellow powder with the help of the dual embedding method were optimized.By measuring the retention rate of peptide and oxidation resistance with different temperatures and humidity,stability of the produced microcapsule was studied.ResultsBased on the comparison between different zymolyte in terms of degree of hydrolysis,spleen lymphocytes proliferation index(SI),the first and secondary structures of amino acid,trypsin was determined as the optimal enzyme used to extract immunopeptide.Meanwhile,the degree of hydrolysis and spleen lymphocytes proliferation index(SI)of trypsin were respectively 10.70% and 1.679,with the activity releasing locus at the α-helix.The optimal technique conditions to produce immunopeptide of the maize yellow powder were shown as follows: enzyme concentration was 3.0g/L,substrate concentration was 60 g/L,temperature was 45 ℃,p H value equaled to 8.0,hydrolysis lasted for 90 minutes with a degree of hydrolysis as 11.40%.The purification conditions for immunopeptide of the maize yellow powder were illustrated as below: p H value was 5.0,concentration of immunopeptide solution of the maize yellow powder was 10 mg/m L,flow rate of the sample was 0.5 m L/min,concentration of the ethyl alcohol eluant was 70%.The desalinization rate was measured as(91.20±0.06)% and the recovery rate of peptide was(80.04±0.03)%,showing a good immunological competence of immunopeptide desalted under the above conditions.The technical conditions to produce microcapsule were shown as below: ultrasonic time was 30 minutes,ultrasonic power was 145 W,mass ratio between peptide and porous starch was 3:10,solid matter content was 18% and content of added xanthan gum was 0.5%.The embedding rate reached up to 70.52%.Stability study of microcapsule: after stored for 30 days,the retention rate of active peptide for microencapsulation under the humidity of 33% was(88.42±0.18)%,the retention rate of active peptide for microencapsulation under the temperature of 4 was(89.22±0.07)%.And the clearance rate and ℃reducing capacity of microcapsule against DPPH free radical were respectively 45% and 0.56.Two conclusions were drawn: One is that microcapsule needs to be stored under the condition of low temperature and humidity.The other is microencapsulation can effectively increase the stability of peptide.ConclusionsThe technique conditions to produce immunopeptide of the maize yellow powder were shown as follows: enzyme concentration was 3.0 g/L,substrate concentration was 60 g/L,temperature was 45 ℃,p H value equaled to 8.0,hydrolysis lasted for 90 minutes,extracted by trypsin hydrolysis.Immunopeptide of the maize yellow powder as the result of macroporous resin purification and desalination could enhance the capability of spleen lymphocyte proliferation for mice and was dose-dependent.The immunopeptide microcapsule of the maize yellow powder produced under a condition where the ultrasonic time is 30 minutes,the ultrasonic power is 145 W,the mass ratio between peptide and porous starch is 3:10,the solid matter content is 18% and the content of added xanthan gum is 0.5% can keep immunopeptide’s resistance to oxidation as well as effectively improve its stability.