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

Objective:To test the feasibility that the direct determination of protein content in raw milk by rapid titration and the interference degree of adulteration to this method, which can provide a quick and effective way to 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 and the Kjeldahl method to verify the accuracy of the results. Results:Results showed in the process of titration, 1.00 mL sample, with 1.00 mL 0.1mol/L HCl to control acidity, consumed 4.50 mL 0.2%SDS, the ideal results were obtained by second titration. Compared with Kjeldahl determination and TNM-1 instrument method, the results had no significant difference (p>0.05) . On the basis of kjeldahl determination, quantitative relationship between the two methods was obtained, namely costing 1.00 mL 0.2% SDS was equivalent to 7.53 ×10-3g protein. A certain concentration range of non-protein nitrogen dopant had no obvious effect on the determination of raw milk protein. Conclusion:The operation of this method was simple, the result was accurate, and it could meet the acceptance of raw milk, a large number of samples of milk quality measurement and real-time control the milk quality, with a very significant application value in dairy production.