Nestlé Research Center, Lausanne, Switzerland.
The Children's Medical Institute, National University Hospital, Singapore.
J Sep Sci. 2018 Apr;41(8):1805-1811. doi: 10.1002/jssc.201700833. Epub 2018 Feb 9.
Human milk provides the key nutrients necessary for infant growth and development. The objective of this study was to develop and validate a method to analyze the cholesterol content in liquid human milk samples along lactation. Direct saponification of the sample using ethanolic potassium hydroxide solution under cold conditions was applied and unsaponifiable matter was separated by centrifugation. Cholesterol was converted into its trimethylsilyl ether and the derivative analyzed by gas chromatography coupled with a flame ionization detector. Cholesterol was quantified using epicoprostanol as internal standard. The method is suitable for the determination of cholesterol in only 0.3 g of human milk. It has been validated showing good repeatability (CV(r) < 15%) and intermediate reproducibility (CV(iR) < 15%). The method was used to analyze human milk obtained from five mothers collected at day 30(±3), 60 (±3) and 120 (±3) after delivery. The cholesterol content in human milk slightly decreased from 13.1 mg/100 g at 1 month to 11.3 mg/100 g 120 days after delivery. The method can also be used to determine desmosterol, an intermediate in cholesterol synthesis.
人乳提供了婴儿生长和发育所需的关键营养物质。本研究的目的是开发和验证一种分析哺乳期液体人乳样本中胆固醇含量的方法。采用乙醇氢氧化钾溶液在冷条件下直接皂化，通过离心分离不皂化物。胆固醇转化为三甲基硅醚衍生物，并用气相色谱-火焰离子化检测器进行分析。胆固醇用依普前列腺素作为内标定量。该方法适用于仅 0.3 g 人乳中胆固醇的测定。该方法已得到验证，具有良好的重复性（CV(r) < 15%）和中间重现性（CV(iR) < 15%）。该方法用于分析分娩后第 30(±3)、60(±3)和 120(±3)天的 5 位母亲的人乳。人乳中的胆固醇含量从分娩后 1 个月的 13.1 mg/100 g 略有下降到 120 天的 11.3 mg/100 g。该方法还可用于测定胆固醇合成中的中间产物——去甲胆甾醇。
