Dried milk protein products. Determination of nitrogen solubility index

2002 ◽  
Keyword(s):  
Milk Protein ◽  
Nitrogen Solubility ◽  
Nitrogen Solubility Index

An improved method for determining the nitrogen solubility of caseinates

1990 ◽  
Vol 57 (2) ◽  
pp. 207-212
Author(s):  
Wolfgang Kneifel ◽  
Anne Beurel
Keyword(s):  
Filter Paper ◽  
Nitrogen Solubility ◽  
New Method ◽  
Nitrogen Solubility Index ◽  
Improved Method

SummaryThe nitrogen solubility index (NSI) method for the examination of caseinates was evaluated. It was found that widely scattering NSI values are mainly due to ineffective centrifugation and filtration of the caseinate dispersion. In order to avoid this, an improved combined centrifugation–filtration procedure was developed as an alternative to the original NSI method, using an Amicon micropartition system MPS-1 equipped with discs of filter paper. The micropartition devices can be centrifuged in a Gerber centrifuge of the type used for butyromctric fat determination. Several types of caseinates were evaluated with the new method and yielded a markedly smaller range of single values than were obtained with the NSI method.

369. Determination of the free amino-nitrogen of casein and of fresh and deteriorated milk protein by the Van Slyke method

1948 ◽  
Vol 15 (3) ◽  
pp. 364-368 ◽  
Author(s):  
C. H. Lea
Keyword(s):  
Constant Temperature ◽  
Nitrous Acid ◽  
Free Amino ◽  
Milk Protein ◽  
Technical Assistance ◽  
Milk Powder ◽  
Amino Nitrogen ◽  
Industrial Research ◽  
Simplified Procedures

The reaction of casein and of fresh and deteriorated milk protein with nitrous acid has been followed at constant temperature for 4 hr. in the manometric apparatus of Van Slyke, and simplified procedures suggested whereby the method can be utilized for investigation of the deterioration of the protein of separated milk powder during storage.Technical assistance in this work was given by Mr L. J. Parr: The work was carried out as part of the programme of the Food Investigation Board of the Department of Scientific and Industrial Research.

scholarly journals Determination of Effects of Milk Protein Genotype on Production Traits of Israeli Holsteins

1994 ◽  
Vol 77 (4) ◽  
pp. 1106-1113 ◽  
Author(s):  
M. Ron ◽  
O. Yoffe ◽  
E. Ezra ◽  
J.F. Medrano ◽  
J.I. Weller
Keyword(s):  
Milk Protein ◽  
Production Traits ◽  
Protein Genotype

The Activity of Nitrogen in the Liquid Fe-N-Cr Alloy Based on the Non-Random Solubility Model by Schmid - Fetzer

2010 ◽  
Vol 638-642 ◽  
pp. 3021-3025
Author(s):  
J. Siwka ◽  
A. Hutny
Keyword(s):  
Chromium Content ◽  
Nitrogen Solubility ◽  
Energy Parameter ◽  
Original Data ◽  
Standard State ◽  
Pure Nitrogen ◽  
Temperature Function ◽  
Solubility Model ◽  
Function Relationship

The values of nitrogen solubility in the liquid Fe-N-Cr alloy and in liquid chromium were determined experimentally. The alloy of a chromium content of 8; 13; 18; 25; 35; and 69, respectively, and chromium of purity of 99.7 wt % were subjected to experiment. The original data on nitrogen solubility in liquid iron and the data on nitrogen solubility in liquid chromium (the authors' own studies) were converted in relation to the new standard state that is represented by pure nitrogen. The energy parameter, h Fe-Cr, was determined based on literature data. Using the coefficient values for the Fe-Cr alloy, calculated on the basis of our own investigation results, the values of the energy parameter h were determined. The determined energy parameter h in the form of a temperature function relationship will enable the determination of the numerical values of the for the Fe-Cr alloy of any arbitrary composition.

Simultaneous Determination of Vitamins D2 and D3 by Electrospray Ionization LC/MS/MS in Infant Formula and Adult Nutritionals: First Action 2012.11

2013 ◽  
Vol 96 (6) ◽  
pp. 1387-1395 ◽  
Author(s):  
Donald L Gilliland ◽  
Charles K Black ◽  
James E Denison ◽  
Charles T Seipelt ◽  
Steve Baugh
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Potassium Hydroxide ◽  
Milk Protein ◽  
Method Detection Limit ◽  
Quantitation Limit ◽  
Alcoholic Potassium Hydroxide ◽  
High Level ◽  
Analysis Of Vitamins

Abstract A method was developed for the analysis of vitamins D2 and D3 in a variety of nutritional products. To extract vitamins D2 and D3 from products containing substantial amounts of fat, a saponification with alcoholic potassium hydroxide is required to release the vitamin D. Trideuterium- labeled vitamin D is added to the sample prior to saponification, and quantitation is achieved using linear regression of the ratio of peak response for 2H3-D and vitamin D. Acceptable linearity was achieved between 0.6 and 27 μg/100 g with a correlation requirement of >0.999. The method detection limit of 0.02 μg/100 g was verified by spiking placebo products carried through the saponification and extraction steps of the method. At the quantitation limit (0.12 μg/100 g), the signal was easily distinguished from the background. Vitamin D3 spike recoveries ranged from 107 to 119% at the low level and 104 to 116% at the high-level spike. Vitamin D2 recoveries were 105 to 116% and 91 to 110% for the low- and high-level spikes, respectively. SRM 1849a has a certified concentration of 11.1 ± 1.7 μg/100 g; using this standard reference material, the range of 9.4 to 12.8 μg/100 g was met on each of the 6 days. Method repeatability, determined in 12 vitamin D3 product matrixes over 6 days, ranged from 3.9 to 48%. The adult nutrition-milk protein sample was the most notable; it failed within-day, as well as day-to-day, precision requirements. There was no attempt to optimize the sample preparation to accommodate any problem matrix.

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