Study On The Preparation And Antioxidant Of Millet Polypeptide

A kind of millet —— Qiliang millet produced in Datong City,Shanxi Province is used as the research material in this paper.On the basis of single factor experiment and orthogonal experiment,the optimum technological conditions for the solubility of millet alcohol protein by ultrasonic modification were determined.The optimum technological conditions of alkaline protease for the hydrolysis of millet-ol-soluble protein were determined based on single factor experiment and response surface test.With the rapid development of modern society and the rapid acceleration of urban rhythm,people's demand for food is also increasing.Millet is loved by people because of its rich nutritional value,unique health care function and cheap advantages.But at present,the application of millet in China is still in the primary processing stage,the added value of products is low,and the research on millet polypeptide at home and abroad is less reported.This experiment further expands the application scope of millet in food field,provides technical support for millet deep processing,drives local economic development and produces good economic benefits by hydrolyzing the polypeptide in millet and studying its antioxidant properties.The main findings are as follows:1?Optimization of Ultrasonic Modification on Solubility of Millet Soluble Protein.Four independent variables were set up to ultrasonic time,ultrasonic power,ultrasonic temperature,p H,single factor experiment was carried out according to the condition of four independent variables,and Coomassie brilliant blue colorimetry was used to measure the value of millet alcohol solubility protein.Absorption was used as a reference index,and the optimum solubility parameters of millet protein were obtained.the protein solution p H7.5,set ultrasonic time 17.5 min,ultrasonic temperature 45?,ultrasonic power 83%,under this condition,the solubility of millet alcohol soluble protein was 0.275 ±0.002mg/m L,the solubility increased 7.24±0.49 times.2?Optimization of the process of alkaline protease for the solubility of small miol protein.Millet alcohol soluble protein preparation solution.Using formaldehyde titration,and the water solubility of millet alcohol soluble protein as a reference index.In this experiment,three independent variables were set up for substrate concentration,enzyme bottom,hydrolysis time.According to the conditions of three independent variables,the conditions for response surface test can be obtained: substrate concentration(3.0,4.0,5.0)%,enzyme bottom ratio(1.5,2,2.5)%,hydrolysis time(1,1.5,2)h.The response surface test was designed and carried out according to the single factor test data of alkaline protease hydrolysis.The optimum process parameters for the optimization of the solubility of millet alcohol in protein by white enzyme were as follows: hydrolysis time 1 h30 min,substrate concentration 4%,enzyme bottom ratio 2%.at this time,the hydrolysis degree of millet alcohol soluble protein reached 47.13%±0.05%.3?Sephadex G-50 gel separation of millet peptides.The molecular weight of Millet Soluble Protein and Millet Polypeptide was measured in 20.1 k Da~66.2 k Da?14.4k Da~20 k Da by non-reduction and reduction electrophoresis.Three peaks of millet peptides were separated by Sephadex G-50 gel,and the absorptivity of the three peaks was :0.413±0.002 Abs?0.425±0.003Abs?0.244±0.003 Abs.4?Determination of antioxidant properties of millet peptides.The antioxidant properties of four free radical scavenging rates(including DPPH· radical,superoxide anion radical,ABTS+· radical,hydroxyl radical)were studied together with millet polypeptide enzymatic hydrolysis stock solution to separate three peaks of millet polypeptide.The following two conclusions were drawn:1.The enzyme hydrolysate of millet peptide has a certain antioxidant function,and the antioxidant capacity of each component peptide liquid collected by chromatography has a certain improvement compared with the enzyme hydrolysate,and the smaller the relative molecular weight of millet peptide,the stronger the ability of scavenging free radicals,that is,the stronger the antioxidant capacity.2.Different molecular weight peptides have different scavenging rates to different free radicals,indicating that different molecular weight peptides have different antioxidant,among which the scavenging rate to ABTS+· free radicals is the highest.