快速滴定法测定原料乳蛋白质的条件控制

The condition control for determination of protein in raw milk by rapid titration

目的:实验快速滴定法直接测定原料奶中蛋白质含量的可行性及掺杂物对该法的干扰程度,为原料奶验收和大批量样品检测提供快速有效的测定方法。方法:分别对快速滴定法的测定条件、操作步骤、终点判定进行反复实验,采用干燥法和凯氏定氮法对结果准确性进行验证。结果:样品取样量为1.00mL,用1.00mL 0.1mol/L盐酸控制酸度时,采用2次滴定法,消耗4.50mL 0.2%SDS,得到理想结果;与凯氏定氮法和仪器法所得结果相比,无显著差异(p>0.05)。以凯氏定氮法为标准,得到两种方法之间的数量关系,即消耗1.00mL 0.2%SDS相当于含蛋白质7.53×10-3g。一定浓度范围内的非蛋白氮掺杂物对快速滴定法测定原料奶中蛋白质的含量也无明显影响。结论:本法操作简便、结果准确,可满足原料奶验收、大批样品测定和实时掌控牛奶品质状况的要求,在奶业生产领域具有非常明显的推广应用价值。

Objective ：To test the feasibility that the direct determination of protein content in raw milk by rapidtitration and the interference degree of adulteration to this method,which can provide a quick and effective wayto accept the raw milk and test a large number of sample. Methods To research the determination condition,operation steps,and the endpoint determination of rapid titration by trial and error,using the dry method andthe Kjeldahl method to verify the accuracy of the results. Results=Results showed in the process of titration,1.00mL sample,with 1.00mL 0.1mol/L HCI to control acidity,consumed 4.50mL 0.2%SDS,the ideal results wereobtained by second titration. Compared with Kjeldahl determination and TNM-1 instrument method,the resultshad no significant difference（p〉0.05）. On the basis of kjeldahl determination,quantitative relationship betweenthe two methods was obtained,namely costing 1.00mL 0.2% SDS was equivalent to 7.53x10^4g protein. Acertain concentration range of non-protein nitrogen dopant had no obvious effect on the determination of rawmilk protein. Conclusion=The operation of this method was simple,the result was accurate,and it could meetthe acceptance of raw milk,a large number of samples of milk quality measurement and real-time control themilk quality,with a very significant application value in dairy production.