应用浊度法快速鉴别原料乳、巴氏乳和UHT乳

试验采用浊度法来鉴别原料乳、巴氏乳及UHT乳。螯合盐对不同热处理的牛乳处理后显示出不同的浊度，根据这一特性筛选出可以较好区分原料乳、巴氏乳及UHT乳的螯合盐，该检测方法的原理为螯合盐主要通过螯合了牛乳中的钙、对酪蛋白胶粒进行了分散，并形成了一种新的螯合盐和钙的复合物，改变了酪蛋白的特性。结果显示柠檬酸盐（柠檬酸三钠、柠檬酸铵）和磷酸盐（六偏磷酸钠、多聚磷酸钠、焦磷酸钠）可以很好将牛乳中的酪蛋白胶粒进行分散，分散后的胶体溶液呈现出可以定量测量的浊度，但柠檬酸三钠对原料乳、巴氏乳和UHT乳分散后浊度的区分最为明显，D_{600 nm}值在0～0.15之间为原料乳，0.20～0.50之间为巴氏乳，0.60～1.00之间为UHT乳。浊度法可以快速的鉴别原料乳、巴氏乳和UHT乳，且操作简便，检测速度快，费用低。

Rapid Identification of Raw Milk,Pasteurized Milk and UHT Milk Using Turbidity Method

The objective of this study was to identify raw milk, pasteurized milk and UHT milk using turbidity method. There is difference of turbidity after adding chelating salts in different heat treatment milk. So, according to this feature, screening out chelating salts that can be used to differentiate raw milk, pasteurized milk and UHT milk is essential. The results showed that citrates (trisodium citrate, ammonium citrate) and phosphates (sodium hexametaphosphate, sodium polyphosphate, sodium pyrophosphate) could disperse casein micelles and present quantitatively turbidity. However, trisodium citrate on raw milk, pasteurized milk and UHT milk turbidity distinguished most significantly, absorbance 600 value between 0 to 0.15 was raw milk, absorbance 600 value between 0.20 to 0.50 was pasteurized milk, absorbance 600 value between 0.60 to 1.00 was UHT milk. The main mechanism of this mehod included chelation of CN-bound Ca, dispersion of CN micelles, and formation of new types of calcium-chelating salts complexes. Turbidity method can identify raw milk, pasteurized milk and UHT milk fast, conveniently and more cheaply.