碱水解法测定乳及乳制品中脂肪的含量

Determination of fat content in milk and dairy products by alkaline hydrolysis

中文关键词:  乳及乳制品  脂肪  碱水解法  罗紫-哥特里法

英文关键词:milk and dairy products  fat  alkaline hydrolysis  Rose-Gottlieb method

中文摘要:

      目的 建立简单、快速的碱水解法测定乳及乳制品中脂肪的含量。方法 取0.5 g样品于离心管中, 用10 mL纯水复溶后加入2 mL氨水(25%)水解并65 ℃水浴20 min。加入乙醇沉淀蛋白质并使用乙醚、石油醚提取样品中脂肪。将上清液提取至收集瓶中, 蒸干提取液, 称量收集瓶前后质量, 计算样品中脂肪含量。 结果 此法测得样品脂肪含量为26.53 g/100 g, 结果相对偏差为0.37%。测定值在质控样品值满意区间内, 且符合国标规定的两次独立测定结果之差≤0.3 g/100 g的要求。结论 本法测定乳及乳制品中脂肪的含量具有简便、快速、重现性好的优点, 适合实验室日常样品测定及考核使用。

英文摘要:

      Objective To establish a simple and rapid alkaline hydrolysis method for the determination of fat content in milk and dairy products. Methods 0.5 g sample was taken in a centrifuge tube, redissolved with 10 mL pure water, then 2 mL ammonia water (25%) was added for hydrolysis and water bath at 65 ℃ for 20 min. Ethanol was added to precipitate the protein and ether and petroleum ether were used to extract the fat in the sample. Extract the supernatant into a collecting bottle, evaporate the extractive solution, weigh the mass before and after the collecting bottle, and calculate the fat content in the sample. Results The fat content of the sample measured by this method was 26.53 g/100 g, and the relative deviation was 0.37%. The measured value was within the satisfactory range of the quality control sample value, and meets the requirement specified by the national standard that the difference between the two independent measurement results was less than or equal to 0.3 g/100 g. Conclusion This method is simple, rapid and reproducible for the determination of fat in milk and dairy products. It is suitable for routine laboratory sample determination and examination.