Quality Analysis Study Of Key Nutrients In Infant Milk Powder

Infant formula milk (IFM) products were developed to meet special nutrient needs ofinfants, based on ordinary milk powders. The main raw materials of IFM was skim milkpowder, whey protein powder, soy protein powder, sucrose, lactose etc., with someadditional supplements such as proper amounts of vitamins and minerals. It was critical tomonitor multiple components of IFM for its quality control. The present thesis focused onintroduction of quality analysis methods of IFM, including the contents of proteins, fats,minerals and luteins.Nine kinds of minerals, Na, Mg, P, K, Ca, Mn, Fe, Cu and Zn in IFM were determinedusing inductively coupled plasma mass spectrometry (ICP-MS). The method was evaluatedincluding the linear correlation, precision, stability and accuracy of the method. The resultswere obtained as follows: the linear correlations of nine minerals were satisfied within theconcentration ranges investigated, with R2all greater than0.9995; the precision andstability results were both good, with RSD values of Na, Ca, K to be0.29%,0.67%,0.99%and0.35%,0.15%,0.94%, respectively; accuracy test also gave good data, for example,the6test results of RSD of the third point was only0.15%. The methods developed wereapplied in sample analysis with success.A HPLC method was established for determination of lutein in IFM. A YMCCarotenoid S5(4.6mm i.d.250mm) column was applied; the mobile phase wasmethanol (A)-tert-butyl methyl ether (B), with graduate elution of15%B (0-15min),90%B (15.02-19min), and15%B (19.02-20min); An agilent G1314A UV detector wasapplied, with the detection wavelengths setting at445nm; the flow rate and columntemperature was set at1.0mL/min and23C, respectively; and sample volume was100μL. As a result, the linear range for lutein was5–50μg/100g milk, with the averagerecovery to be98.95%. Under this condition, the content of lutein in3batches of IFMsamples was determined to be194.76μg/100g. The contents of proteins and fats in IFM were also measured using the Kjeldahl andSoxhlet extraction methods, respectively. Finally, full inspection reports of3batches ofcommercially available IFM products were conducted as an example. The qualityinspection results of key nutrients in IFM were introduced, including vitamins, lutein,minerals etc. These results were helpful for development of quality control methods ofIFM.