Protein Nitrogen Determination

2003 ◽  
pp. 33-38
Author(s):  
S. Suzanne Nielsen
Keyword(s):  
Protein Nitrogen ◽  
Nitrogen Determination

Direct and Indirect Determination of True Protein Content of Milk by Kjeldahl Analysis: Collaborative Study

1991 ◽  
Vol 74 (2) ◽  
pp. 281-288 ◽  
Author(s):  
David M Barbano ◽  
Joanna M Lynch ◽  
J Richard Fleming
Keyword(s):  
Nitrogen Content ◽  
Protein Content ◽  
Total Nitrogen ◽  
Collaborative Study ◽  
Total Nitrogen Content ◽  
Nonprotein Nitrogen ◽  
Protein Nitrogen ◽  
Nitrogen Determination ◽  
True Protein

Abstract Currently, the reference procedure for determination of the "protein" content of milk is based on measurement of the total nitrogen content of milk by the Kjeldahl method (AOAC method, 920.105). About 6% of the total nitrogen content of milk Is nonprotein nitrogen. Therefore, total nitrogen multiplied by the conversion factor 6.38 overestimates the true protein content of milk on average by about 6%. In the present study, new direct and Indirect methods were developed for measurement of the true protein content of whole milk by Kjeldahl nitrogen determination. Both new methods are sample preparation procedures used to fractionate the nitrogen-containing compounds In milk prior to measurement of the nitrogen content of these fractions by Kjeldahl analysis. The collaborative study consisted of 9 pairs of blind duplicate milk samples that were analyzed for total nitrogen, nonprotein nitrogen, and protein nitrogen by each of 10 laboratories. Both methods for true protein measurement (direct and Indirect) gave acceptable statistical performance characteristics and good agreement between methods. The new direct method requires about half the laboratory analysis work of the indirect method (i.e., total minus nonprotein nitrogen). The methods have been adopted official first action by AOAC as (1) a new method for nonprotein nitrogen determination in milk, (2) a new method (direct) for determination of protein nitrogen content of milk, and {3) an alternative method (indirect) for determination of protein nitrogen content of milk.

Suitability of the hach1Kjeldahl modification for protein nitrogen determination of periphyton communities

Biofouling ◽  
1990 ◽  
Vol 2 (1) ◽  
pp. 87-92
Author(s):  
C I Ridley‐Thomas ◽  
A P Austin ◽  
Wm P Lucey ◽  
M J R Clark
Keyword(s):  
Protein Nitrogen ◽  
Nitrogen Determination

Protein Nitrogen Determination by Kjeldahl Digestion and Ion Chromatography

2016 ◽  
Vol 105 (6) ◽  
pp. 1851-1857 ◽  
Author(s):  
Hsiaoling Wang ◽  
Nagarani Pampati ◽  
William M. McCormick ◽  
Lokesh Bhattacharyya
Keyword(s):  
Ion Chromatography ◽  
Protein Nitrogen ◽  
Nitrogen Determination ◽  
Kjeldahl Digestion

scholarly journals Non-protein nitrogen determination: A screening tool for nitrogenous compound adulteration of milk powder

2017 ◽  
Vol 68 ◽  
pp. 46-51 ◽  
Author(s):  
Jonathan W. DeVries ◽  
George W. Greene ◽  
Anitra Payne ◽  
Steven Zbylut ◽  
Peter F. Scholl ◽  
...  
Keyword(s):  
Screening Tool ◽  
Milk Powder ◽  
Protein Nitrogen ◽  
Nitrogenous Compound ◽  
Nitrogen Determination

Effect of Non-protein Nitrogen Supplementation of Low-protein Layer Diets

1977 ◽  
Vol 14 (5) ◽  
pp. 250-255
Author(s):  
Hiroyuki MEKADA ◽  
Isao UMEDA ◽  
Nobuyoshi HAYASHI ◽  
Jun-ichi OKUMURA ◽  
Hiro-omi YOKOTA
Keyword(s):  
Protein Layer ◽  
Protein Nitrogen ◽  
Nitrogen Supplementation ◽  
Low Protein

scholarly journals THE ESTIMATION OF NON-PROTEIN NITROGEN IN BLOOD

1918 ◽  
Vol 34 (1) ◽  
pp. 97-101
Author(s):  
Isidor Greenwald
Keyword(s):  
Protein Nitrogen

scholarly journals A STUDY OF THE NON-PROTEIN NITROGEN OF WHEAT FLOUR

1918 ◽  
Vol 33 (3) ◽  
pp. 551-559
Author(s):  
M.J. Blish
Keyword(s):  
Wheat Flour ◽  
Protein Nitrogen
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