Evaluation of Automated Dye Binding Determination of Protein in Milk

1974 ◽  
Vol 57 (1) ◽  
pp. 42-47
Author(s):  
Douglas L Park ◽  
Raymond L King
Keyword(s):  
Protein Content ◽  
Mercuric Chloride ◽  
Sampling Rate ◽  
Protein Determination ◽  
Binding System ◽  
Milk Samples ◽  
Instrument Performance ◽  
Dye Binding ◽  
Herd Milk

Abstract The Technicon AutoAnalyzer dye binding system for protein determination in milk was compared with the Kjeldahl and Udy methods. Individual cow and mixed herd milk samples were analyzed, including such variables as the effect of aging, chemical preservation, laboratory manipulation of protein content, and experimental changes in instrumental parameters. The Udy and Kjeldahl methods showed better agreement than the Technicon procedure in all treatments. Aging resulted in slight decreases in apparent protein content by both dye binding methods. Variation due to treatment with formaldehyde and mercuric chloride was considerable for the Technicon system (+ 0.72 and +0.20% protein, respectively). Individual cow milks varied more than herd milks and Guernsey more than Holstein milk. Milk samples standardized for protein content showed a high correlation with the Kjeldahl results. Replication by the Technicon system was superior to both the Udy and Kjeldahl methods. Performance of the Technicon system improved with increased dialyzing time, decreased dye concentration, and decreased sampling rate. Instrument performance was also influenced by dialysis membrance replacement.

scholarly journals Analysis of Fat and Protein Content in Milk Using Laser Polarimetric Scatterometry

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1028
Author(s):  
Alexey V. Shkirin ◽  
Dmitry N. Ignatenko ◽  
Sergey N. Chirikov ◽  
Nikolai F. Bunkin ◽  
Maxim E. Astashev ◽  
...  
Keyword(s):  
Protein Content ◽  
Dairy Production ◽  
Size Distributions ◽  
Fat Percentage ◽  
Milk Samples ◽  
Quantitative Content ◽  
Scattering Matrices ◽  
Control Milk ◽  
Dairy Cow Nutrition

Monitoring the composition of milk products is an important factor in the management of dairy farms and industry. Information on the quantitative content of milk components is necessary to control milk quality, as well as to optimize dairy cow nutrition and diagnose their clinical condition. The content of fat and protein is considered the main criterion for determining the market value of milk. Increasing the efficiency of dairy production requires the use of inexpensive and compact devices that are capable of performing multicomponent analysis of milk both directly on the farm and in technological lines. We investigated the possibility of fast simultaneous determination of fat and protein content in milk by laser polarimetric scatterometry. The block-diagonal elements of the scattering matrix were measured for a series of commercially produced milk samples with the indicated fat percentage, which were diluted by volume with water. From the measured scattering matrices, the size distributions of fat droplets and casein aggregates were reconstructed. Using the size histograms, the content of fat and protein and protein-to-fat ratio in the studied milk samples are estimated.

Rapid Tests for Protein in Milk

1963 ◽  
Vol 46 (4) ◽  
pp. 743-744
Author(s):  
Charles A Kiddy ◽  
R D Plowman
Keyword(s):  
Protein Content ◽  
Rapid Determination ◽  
Dye Binding ◽  
Rapid Tests

Abstract A study of dye-binding methods for the rapid determination of the protein content of milk is being initiated. Preliminary studies are discussed; further study is recommended.

scholarly journals A simple rapid method for protein determination

2013 ◽  
Vol 42 (1-2) ◽  
pp. 183-190
Author(s):  
Janusz Czapski
Keyword(s):  
Protein Content ◽  
Linear Function ◽  
Rapid Method ◽  
Optical Density ◽  
Insoluble Residue ◽  
Protein Determination ◽  
Amido Black 10B ◽  
Amido Black ◽  
The Difference

A simple, rapid method is described for determination of protein in the range of 20-200 µg. The procedure is based on the reaction between protein and amido black 10B. An insoluble residue is precipitated and the dye concentration in solution decreases. The difference between the optical density of the blank (without protein) and sample with protein is a linear function of protein content.

Collaborative Study of the Pro-Milk Method for the Determination of Protein in Milk

1975 ◽  
Vol 58 (4) ◽  
pp. 770-772
Author(s):  
John W Sherbon
Keyword(s):  
Protein Content ◽  
Collaborative Study ◽  
Good Precision ◽  
Milk Samples ◽  
Solution Studies ◽  
Dye Solutions

Abstract Seven milk samples and 2 standard dye solutions were analyzed for protein content by the Pro-Milk method by 6 collaborating laboratories. Interlaboratory variations, although small, were significant, probably because of extremely good precision. Blind duplicates (2 sets) did not differ from each other. Tests of dilute dye solutions, involving only the colorimeters, showed interlaboratory variation, which indicates the need to carefully calibrate each instrument. The magnitudes of the variations encountered in the milk and dye solution studies were sufficiently small to allow adoption of the Pro-milk method as official first action.

Use of the Fossomatic Somatic Cell Counts in a Mastitis Control Program1

1977 ◽  
Vol 40 (7) ◽  
pp. 490-492 ◽  
Author(s):  
G. M. JONES ◽  
C. W. HEALD ◽  
W. N. PATTERSON ◽  
D. E. ROBINSON
Keyword(s):  
Somatic Cell ◽  
Dairy Herd ◽  
Cow Milk ◽  
Average Percentage ◽  
Somatic Cell Counts ◽  
Milk Samples ◽  
Cell Counts ◽  
Herd Milk ◽  
Mastitis Control

The Fossomatic determination of somatic cells present in individual cow milk samples was instituted in the Virginia Dairy Herd Improvement testing program in June, 1976. During the first 6 months the average count was 449,060 cells/ml for 113,735 observations. The average percentage of cows according to ranges in cell counts was: under 150,000, 47.9%; 150–400,000, 25.8%; 400–800,000, 12.5%; 800–1,500,000, 7.2%; and over 1,500,000, 6.6%. The percentage of cows with less than 150,000 cells/ml was reduced for September, 1976. On a herd basis, 66% averaged less than 500,000 cells/ml, 30% between 500 to 1,000,000, and 4% exceeded 1,000,000. The percentage of herds with less than 500,000 cells/ml decreased from June to September, 1976 but increased in October. Quarters infected with primary pathogens were estimated by Westgarth's equation to be 10.4% resulting in a calculated 5% reduction in total herd milk production. Procedures are described which would assist dairymen in the interpretation of somatic cell counts.

Collaborative Study of the Kjeldahl Method for Determination of Protein Content of Milk

1969 ◽  
Vol 52 (1) ◽  
pp. 126-130
Author(s):  
D R Strang ◽  
J W Sherbon
Keyword(s):  
Statistical Analysis ◽  
Standard Deviation ◽  
Protein Content ◽  
Analysis Of Variance ◽  
Collaborative Study ◽  
Protein Analysis ◽  
Average Standard Deviation ◽  
Milk Samples ◽  
Kjeldahl Method

Abstract Nitrogen in 12 milk samples was measured in 19 laboratories by the Kjeldahl method. Three of the 19 laboratories were excluded from statistical analysis because the nitrogen values they reported differed markedly from those reported by the remaining 16 laboratories. The average standard deviation for the determinations was 0.012% nitrogen, which is equal to 0.077% protein. Analysis of variance indicated that the error due to the laboratories effect was significant when 16 laboratories were considered. When the laboratories were sorted according to various experience criteria, the variations due to laboratories were significant. When the laboratories were blocked according to catalyst used, the variation among laboratories was not significant.

A comparison of the hydrometric and gravimetric methods for the determination of solids-not-fat when applied to the milk of individual cows in a single herd

1961 ◽  
Vol 28 (2) ◽  
pp. 109-115 ◽  
Author(s):  
R. A. Edwards
Keyword(s):  
Protein Content ◽  
Correction Factor ◽  
Gravimetric Method ◽  
Cow Milk ◽  
Total Solids ◽  
Milk Samples ◽  
Stage Of Lactation ◽  
Solids Content ◽  
Main Factor

SummaryFive hundred and sixty-nine individual cow milk samples from forty-five cows in a single herd were analyzed for fat by the Gerber method, and solids-not-fat by a standard gravimetric method and by the two commonly used British hydrometric techniques. Three hundred and four of the samples were analyzed also for lactose, protein and ash. Large differences between the total solids values obtained by the hydrometric and gravimetric methods were recorded. The magnitude of the differences from the gravimetric values varied with the season of the year and the stage of lactation. The main factor affecting the differences was the protein content of the milk, and equations for the calculation of total solids content incorporating a protein correction factor are given for use if the protein content be known. The hydrometric methods are considered to be of limited use when applied to milks of individual cows.

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