Preparation And Functional Properties Of Desalted Low-hydrolysis Egg White Peptide Powder

China is a major producer and consumer of poultry eggs.The consumption of poultry eggs in China is mainly based on fresh eggs and most of them are directly used,with only a small amount used for deep processing,which seriously restricts the development of the deep processing industry of egg products.On the other hand,the incidence of chronic diseases has increased in recent years.In view of this kind of patient's special diet food like the desalination albumin powder and so on,relies on the import for a long time,and the price is mostly high,the ordinary patient is difficult to bear.Egg white protein in egg white is rich in eight essential amino acids of human body,which is cheap.It is very suitable for protein supplement for patients with chronic diseases,but its high salt content and poor solubility limit the application of egg white in this aspect.Therefore,this project uses egg white powder as raw material to produce egg white peptide with low salt content by enzymatic hydrolysis and ion exchange desalination,aiming at developing high quality egg white powder with low salt,water solubility and good irritability for patients with chronic diseases,and improving the reasonable development and utilization rate of eggs.The main results are as follows:1.Denaturation treatment of egg white protein by heat treatment.The optimum conditions were obtained by single factor and orthogonal experiments with a substrate concentration of 5%,a protein denaturation temperature of 90?,and a protein denaturation time of 20 minutes.2.The degree of hydrolysis and bitter taste value as the index,selection of alkaline protease digestion,low degree of hydrolysis is obtained by single factor and orthogonal experiment and the optimum process conditions of basic no bitter taste of egg white peptide is alkaline protease content is 0.73%,the enzymatic hydrolysis time of 1.3 h,enzyme solution temperature is 55.7 ?,the degree of hydrolysis of 5.78% can be obtained,the bitter taste value score is 1.4,low degree of hydrolysis,basic no bitter taste of the egg white peptide.3.The desalting rate and loss rate of protein as indicators,with ion exchange method,001×7 cation exchange resin and 201×7 anion exchange resin liquid of egg white enzyme solution desalination processing,by single factor test results of optimum condition to ion exchange resin flow of Yin and Yang to 10 BV/h,protein substrate concentration was 3%,the ion of Yin and Yang resin ratio of 2:1,the desalting rate was 87.5%,protein recovery was 73.5%.The 5KDa ultrafiltration membrane was used for desalination.The optimal condition of the single-factor experiment was 0.2MPa ultrafiltration pressure,and the total volume of ultrafiltration was 4.5 times that of the enzymatic hydrolysate.At this time,the desalination rate of the egg white enzymatic hydrolysate was 86.8%,and the protein loss rate was 35.3%.4.The two methods combined with demineralization can finally obtain the enzymatic hydrolysate of egg white with the demineralization rate of 91.3% and protein loss rate of 39.6%.The demineralization effect and protein loss rate of the three demineralization methods are compared.Finally,the ion exchange resin method was used for desalination.For the best desalination program.5.The physicochemical properties of the egg white powder products and the original egg white powder after the treatment were studied and the sensory evaluation and amino acid composition analysis were carried out.From this,it is concluded that the original egg white powder has a great improvement in sensory and physicochemical properties after low-degree hydrolysis of protease,a certain degree of decrease in foaming and stability,and an increase in solubility and thermal stability,and Turbidity is also significantly reduced.