Identification And Control Of Fatty Acids And Nucleotides In Infant And Child Dairy Products

In the process of growth and development,infants have high requirements for fatty acids,nucleotides and other nutrients,but newborns are not able to synthesize these substances themselves,must rely on the external source ingestion supplement.Therefore,infant formula milk powder is required to be nutritionally balanced and comprehensive,and the composition is close to breast milk.Milk fat and nucleotides are important nutrients in milk and dairy products,therefore,it is necessary to focus on detection research.According to the relevant standards and regulations of infant formula food at home and abroad,this paper optimized and established a method for detecting fatty acids and nucleotides.The main contents and conclusions are as follows:1.Thirty-six kinds of fatty acids in formula milk powder were determined by gas chromatography at the same time,the obtained fatty acid chromatogram peak was good,the standard curve of each fatty acid was linear,the correlation coefficient was greater than 0.99,and the relative standard deviation of the parallel samples was less than 10.22%.2.A liquid chromatography-tandem mass spectrometry method was established for the determination of 5 nucleotides in formula milk powder.Samples dissolved in warm water,then add 0.1% formic acid water 5 mL.After ultrasonic extraction,using zinc acetate solution to precipitate the protein,and then filtering with 0.2 ?m filter membrane.The filtrate was separated by a liquid chromatographic gradient elution program,which was separated by ACQUITY UPLC HSS T3(2.1 mm x 100 mm,1.8 ?m)column.Sample volume was 5 ?L.The system flow phase A was 0.1% formic acid aqueous solution,and the flow phase B was 0.1% formic acid acetonitrile solution.The positive ion mode ESI+ was used for the electrospray ion source,the monitoring mode was multi-response monitoring mode(MRM),and the analysis time was 10 min.The obtained nucleotide chromatogram was of good peak type,and the standard curve of each nucleotide was well linear within the concentration range of 0.2~5 ?g/mL,and the correlation coefficient was above 0.99.The recoveries of the samples were between 86%~115%,and the relative standard deviation(RSD)was between 2.22%~9.91%.3.By simulating the transport conditions of infant formula powder and taking transport time and transport temperature as variables,single factor experiments were conducted and conclusions were as drawn:From the perspective of fatty acids,special attention should be paid to the transport conditions of soy-based milk powder during the cross-border transport of infant formula.Bean base powder in transit should be as far as possible to control the temperature below 25?,transport time should be shortened as far as possible;Milk-based milk powder has no strict temperature requirements,but transportation time should be controlled within six weeks.If more than 6 weeks,then the transport temperature should be below 25? low temperature environmentFrom the perspective of the nucleotides,the content of 5 nucleotides in infant formula was significantly affected by the time and temperature during transportation: Since the content of 5 nucleotides in infant formula powder generally increases first and then decreases during the seven transport cycles,it is recommended that the transportation time should not exceed 21 days to ensure the quality of milk powder;Since 5 kind of nucleotides content in infant formula powder under different transportation temperature generally showed a trend of gradual decline,and more than 37 ? temperature drop trend is obvious,we suggest transportation temperature should not be more than 37 ?,and the best transportation temperature should be 0? low temperature environment,in order to guarantee the quality of the milk powder.