Separation And Detection Of Breast Milk Protein Components

Due to the limited depth and breadth of breast milk total casein and total whey protein,systematic and in-depth analysis of the total casein and total whey protein content of healthy breast milk in China and their changing trends are the basis of breast milk research in China.The extraction conditions of total casein and whey protein were optimized.The acid precipitation separation of total whey protein and casein in milk,selected dumas nitrogen determination apparatus for Beijing,hebei,henan,hunan region breast milk whey protein and casein content in the samples for testing;To understand the content of whey protein and casein in each lactation stage and to analyze its change rule and related influencing factors;In addition,variance analysis and multivariate linear regression model were used to analyze the change trend of milk total casein and whey protein content and the related factors influencing its content change.Finally,it is very important to test the content of total protein,whey protein and casein in breast milk for improving infant nutrition and the quality of infant formula.The feasibility analysis of VELP dumas combustion nitrogen determination instrument shows that the detection limit is 0.0192 and the relative standard deviation RSD =0.0064%.Repetitive relative standard deviation RSD<0.5 %;The standard recovery rate is between95.00~102.00 %.Finally experimental conditions of pH 4.6,precipitation time 30 min,the centrifugal temperature 4 ?,10 min,the centrifugal time centrifugal speed 10000 g/min.In different areas in different stages of lactation whey protein and casein content of the research shows that: Whey protein content in breast milk in tongzhou area of Beijing showed a decreasing trend,with the highest 3-5 d(13.91 ±4.59 mg/ml)content,with the content of 1m,3 m and 6 m around 6 mg/ml.Casein content was lowest at 3-5 d(3.08±1.30 mg/ml),12-14 d,and 1m.The content of whey protein in tangshan area of hebei province was the highest at 3-5 d(13.67 ±2.38 mg/ml),decreased at 1 m and lowest at 6 m(5.38±1.32 mg/ml).Casein content was lowest at the 3-5 d(1.77±3.66 mg/ml)stage,highest at the 3 m stage,followed by12-14 d.The content of whey protein in breast milk in luoyang,henan province and liuyang,hunan province was the highest at 3-5 days.Overall,casein content did not change significantly.According to the factors influencing whey protein content and casein content,multivariate linear regression analysis was used to find that,the degree of mother culture,birth weight,pregnancy weight(t = 3.227,2.516,2.519,2.033,P < 0.05)in the breast milk whey protein content change significantly.Its multiple linear regression equation for whey protein = 17.297-3.227 × lactation stage-2.516 × mother culture degree + 2.519 × birth weight + 2.033 × pregnancy weight.Maternal culture(t = 2.203,P<0.05)had significant influence on the concentration of casein in breast milk.The multiple linear regression equation for casein content = 0.781-2.203 × mother culture.