低酸度酒精阳性乳患牛乳汁蛋白组分及氨基酸含量变化

采用聚丙烯酰胺凝胶电泳和酸水解法对低酸度酒精阳性乳患牛乳汁中蛋白组分及17种氨基酸含量进行了测定。结果显示,酒精阳性乳患牛乳汁中总蛋白、SA、lgG-H、-αLG、-βLG相对百分含量无显著变化(P0.05),tCN相对百分含量显著降低(P0.05);在酪蛋白中,-αCN相对百分含量无显著变化(P0.05),-βCN相对百分含量上升(P0.05),-κCN相对百分含量极显著下降(P0.01);17种氨基酸中,Cys含量极显著下降(P0.01),而Arg含量极显著上升(P0.01),Leu含量亦呈上升趋势(P0.05)。结果表明,酒精阳性乳患牛乳汁中主要蛋白组分及氨基酸的含量均发生了变化,乳汁中酪蛋白微球的稳定性遭到了严重破坏,乳汁胶体的稳定性降低,导致酒精试验呈阳性反应。

Changes of proteins and amino acids compotents in milk of dairy cows suffered from APM

Relative percentage contents of proteins and contents of 17 kinds of amino acids in milk of dairy cows suf-fered from alcohol positive milk (APM) were detected by means of polyacrylamide gel electrophones and amino acid analyzer. The result indicated that relative percentage contents of TPR,SA,IgG-H ,α-LG,β-LG in skim milk of dairy cows suffered from APM were no significant changes (P>0.05), relative percentage contents of total casein(tCN) decreases(P(0.05). Relative percentage content of β-CN in casein increased(P<0.05) and relative percentage con-tent of κ-CN decreased markedly (P<0.01). Amino acid analysis data shows that content of Cys decreased markedly (P<0.01) ,but content of Arg increased markedly(P<0.01) ,content of Leu increased (P<0.05). Based on the re-sults,The changes of main milk proteins and contents of amino acids of APM destroy the stability of casein microbal-loons acutely. Decreased stability of milk colloid causes alcohol experiment positive.