Kleyn D H, Ho C L
J Assoc Off Anal Chem. 1977 Nov;60(6):1389-91.
A study was conducted to determine the feasibility of using the qualitative screening method specifying phenolphthalein monophosphate for differentiating reactivated and residual alkaline phosphatase activity. The relative increase in activity of the enzyme in the presence of MgCl2 serves to distinguish reactivated and residual alkaline phosphatase activity. Ten samples each of pasteurized (172 degrees F for 24 sec), sterilized (about 300 degrees F for a minimum of 2 sec) half-and-half and heavy cream were analyzed. Most samples yielded negative results initially but demonstrated activity after incubation 1 hr at 34 degrees C. The average values in terms of + marks, for the half and half and heavy cream in samples without MgCl2 were less than 1 and 2.4, respectively; for samples treated with MgCl2, the values were 2.18 and 4.6, respectively, indicating reactivated phosphatase activity. In samples containing various levels of raw milk, the activity observed in the diluted, Mg2+-containing samples was less than in the undiluted samples containing no Mg, indicating residual phosphatase activity.
进行了一项研究，以确定使用指定磷酸酚酞的定性筛选方法来区分再激活的和残留的碱性磷酸酶活性的可行性。在存在氯化镁的情况下酶活性的相对增加用于区分再激活的和残留的碱性磷酸酶活性。对巴氏杀菌（172华氏度，24秒）、灭菌（约300华氏度，至少2秒）的半脱脂奶和浓奶油各10个样品进行了分析。大多数样品最初产生阴性结果，但在34摄氏度孵育1小时后显示出活性。在不含氯化镁的样品中，半脱脂奶和浓奶油的平均“+”标记值分别小于1和2.4；对于用氯化镁处理的样品，该值分别为2.18和4.6，表明存在再激活的磷酸酶活性。在含有不同水平原料奶的样品中，在稀释的含镁样品中观察到的活性低于不含镁的未稀释样品，表明存在残留的磷酸酶活性。
