进口奶粉与国产奶粉脂肪酸含量的测定和比较

DETERMINATION AND COMPARISON OF FATTY ACIDS IN IMPORTED AND CHINA-MADE MILK POWDER

目的 :研究奶粉中脂肪酸各组分的构成比 ;比较进口奶粉和国产奶粉中脂肪酸构成比 ;对比奶粉标签营养成分表与实际测定结果。方法 :以进口和国产奶粉为研究对象 ,采用气相色谱法进行脂肪酸的分离和测定。结果 :(1)奶粉中共有 2 9种脂肪酸得到确认。 (2 )豆蔻酸、亚油酸、γ-亚麻酸、总不饱和脂肪酸、总多价不饱和脂肪酸及总饱和脂肪酸的含量在进口奶粉和国产奶粉之间差异无显著性意义 (P>0 .0 5 ) ;(3)棕榈酸和硬脂酸含量的差异有显著性意义 (P<0 .0 5 ) ,国产奶粉明显高于进口奶粉 ;油酸和α-亚麻酸含量的差异有显著性意义 (P<0 .0 1) ,进口奶粉明显高于国产奶粉 ;(4 )花生四烯酸在进口奶粉中检出率仅为 5 3.33% ,而在国产奶粉中检出率高达 93.33%。两者差异有显著性意义 (P<0 .0 5 ) ;廿二碳六烯酸在进口奶粉中检出率为 4 6 .6 7% ,而在国产奶粉中均未检出。 (5 )奶粉营养成分表脂肪酸标示值与实际测定值基本一致。结论 :(1)奶粉中脂肪酸基本由 2 0～ 2 9种脂肪酸组成。 (2 )进口奶粉在棕榈酸、硬脂酸、油酸、α-亚麻酸和廿二碳六烯酸等指标上优于国产奶粉 ;国产奶粉在花生四烯酸指标上优于进口奶粉。 (3)

Objective:To study the constituent ratio of fatty acids in imported and domestic milk powder,make comparison between these two results of determination and compare either ones against the formulation of nutrition ingredients listed on the lables.Methods:Separate and determinate the fatty acids by GC in both the imported milk powder and the domestic ones,which are the objects of this study.Results:(1) 29 kinds of fatty acids in milk powder are confirmed.(2) There is no statistical significant difference between the Myristic,Linoleic,γ-Linolenic,Unsaturated Fatty Acid,Polyunsaturated Fatty Acid and Saturated Fatty Acid contents of imported milk powder and those of the domestic ones (P>0.05).(3) Palmitic and Stearic contents in domestic milk powder are obviously higher than those in the imported ones(P<0.05),while Oleic and α-Linolenic contents in both of them are exactly opposite(P<0.01).(4)The proportion of Arachidonic content in imported milk powder is only 53.33%,while 93.33% high in the domestic ones and the difference is significant in statistics(P<0.05).The proportion of DHA content in imported milk powder is 46.67%,while 0% in the domestic ones.(5)The listed value of fatty acids in nutrition ingredients is consistent with the results of inspection.Conclusions:(1) The fatty acids in milk powder are composed of 20～29 kinds of fatty acids.(2)The values of Palmitic,Stearic,Oleic,α-Linolenic and DHA of imported milk powder are superior to those of the domestic ones,while the value of the Arachidonic of the domestic ones are better.(3) The values of fatty acids in milk powder listed on nutrition ingredients lables are quite reliable.