Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Food Sciences


Gary H. Richardson


The Technicon AutoAnalyzer II was evaluated for automatic quantitation of non-casein protein (NCP) in milk. The Lowry method f or colorimetric measurement of proteins was adapted to the automated method and found to be accurate in the determination of non-casein protein in milk. The automated Lowry method obeyed Beer's law. Casein content was calculated by difference between total protein determined by infrared milk analysis (IRMA) and non-casein protein. In the analysis of twenty-five replicate milk samples, the standard deviation was 0.32 and the coefficient of variability was 0.90. The casein content as a percentage of total protein in the milk of cows in the Utah State University dairy herd was found to vary from 41.0 to 81.3%. The automated or continuous flow method was affected by as little as 0.05% (w/w) mercuric chloride, a chemical preservative used in milk, whereas potassium dichromate and formaldehyde had insignificant effects upon the assay.



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