奶粉脱脂前后脂肪酸的比较分析

Comparative Analysis of Fatty Acids before and after Defatting Milk Powder

对奶粉脱脂前后脂肪酸的组成和相对百分含量进行比较分析.采用罗兹-哥特里法提取奶粉中的脂肪油,罗兹-哥特里法利用氨-乙醇溶液破坏奶粉的胶体性状及脂肪球膜,使非脂成分溶解于氨-乙醇溶液中,而脂肪游离出来,再用乙醚、石油醚提取出脂肪油.脂肪油再经氢氧化钾-甲醇溶液甲酯化,用气相色谱-质谱联用法(GC/MS)分析其组成和相对含量.脱脂前奶粉中鉴定出26种脂肪酸,检出率为99.68%,饱和脂肪酸为50.88%,不饱和脂肪酸为48.8%;从脱脂后奶粉中鉴定出13种脂肪酸,检出率为99.30%.饱和脂肪酸为25.56%,不饱和脂肪酸为73.74%.脱脂前奶粉中含饱和脂肪酸比脱脂后奶粉中含饱和脂肪酸多,而脱脂后奶粉中含不饱和脂肪酸比脱脂前奶粉中含不饱和脂肪酸多.

The composition and relative percentage of fatty acids before and after defatting were compared and analyzed.The method of extracting fat oil in milk and dairy products by Roz-gotri method,also known as the alkaline ether extraction method,is to use the ammonia-ethanol solution to destroy the colloid character and fat bulb membrane of milk,so that the non-fat components are dissolved in the solution of ammonia-ethanol,and the fat is free out,and then use ether to extract fat oil.The fat oil is then methylated by potassium hydroxide and methanol solution.Its composition and relative content were analyzed by GC/MS.26 kinds of fatty acids were identified from skim milk powder,the detection rate was 99.68%,the saturated fatty acids were 50.88% and the unsaturated fatty acids were 48.80%.13 kinds of fatty acids were identified from skimmed milk powder,and the detection rate was 99.30%.The saturated fatty acids were 25.56% and the unsaturated fatty acids were 73.74%.The pre-skim milk powder contains more saturated fatty acids than the post-skim milk powder,while the post-skim milk powder contains more unsaturated fatty acids than the pre-skim milk powder.