Determination Of Casein Phosphopeptides By HPLC And Their Effect On Probiotics

The content of casein phosphopeptide in the milk powder has a significant influence on the milk powder including casein phosphopeptide. Casein phosphopeptide functions to promote the absorption of calcium and iron, improve immunity, prevent the body's caries, improve reproductive performance of animal, promote the growth of probiotics and have other biological functions. Hereby in this study, thus the HPLC method was adopted to develop a new method in order to solve the problems including application scope limitation of the traditional testing method..In this research, a method called high performance liquid chromatography(HPLC) was developed to test casein phosphopeptide in the milk powder. We used the Waters e2695 high performance liquid chromatography, matching the Waters 2489 UV detector. In this process, Agilent Eclipse AAA C18 chromatographic column separation was adopted, 5‰ trifluoroacetic acid in acetonitrile / water system was used as the mobile phase in gradient elution, low rate was of 1.00 mL/min, Column temperature was 30?. The linear range obtained by drawing standard curve of casein phosphopeptide was 250~1250 ?g/100 g. The correlation coefficient between R2 was 0.9992~ 0.9998.The method of the minimum detection limits and the minimum quantitative limits were 0.50 mg/100 g and 2.00 mg/100 g.This research acquired the recycling rates by extracting casein phosphopeptide of the milk powder from three water solution, adjusting the pH value, the mobile phase for a 0.45 um filtered water film on, and using standard experimental samples. The range of the average recycling rate of the milk power samples was 99.2%~104%, the average recycling rate was 100.9%. Relative standard deviation scope of the RSD was 2.5%~5.0%. Then the treated samples would be in the fridge and retested after 3 days and 7 days, and it turned out to be that no obvious change occur peak area, retention time, and response value. In this study, first by casein phosphopeptides in infant formula powder dry mixed changes in production processes to analyze the content, after the actual test verifies that the content did not change significantly, Held at 223.0447 ±2.00 mg/100 g and draw quality casein phosphopeptide content control chart.In this study, by comparing the number of live bacteria of Streptococcus thermophilus, Lactobacillus rhamnosus and Bifidobacterium animals in the basal medium, which contains casein phosphopeptide, another contains meat peptone, Three kinds of probiotics had a great number in the basal medium containing casein phosphopeptide than in the basal medium containing meat peptone. Then in the stable phase, the number of viable cells of streptococcus thermophilus were 1.64±0.028×109 and 1.02±0.025×109 cfu/ml; lactobacillus rhamnosus viable count were 2.40±0.025×109 and 1.79±0.011×109cfu/ml; animal bifidobacterium viable count were 1.44±0.020×109 and 0.84±0.031×109 cfu/ml. The average diameter of three kinds of probiotics was 2.0279 mm in the basal medium containing casein phosphopeptide, and that was 1.6808 mm in both medium.