This paper is only available as a PDF. To read, Please Download here.
Summary
A rapid method for estimating the degree of proteolysis in ripening cheese was studied by measuring absorption of ultraviolet light by a clear, sodium citrate-hydrochloric acid extract of cheese at pH 4.4 ± 0.05; these measurements were closely correlated with the per cent of soluble nitrogen in the cheese extract. Measurements of the optical density of the cheese from 40 lots of varying ages revealed peaks of all absorption spectra between 274 and 275 mµ. The coeffieient of correlation between optical density of the cheese extract and percentage of soluble nitrogen measured in the cheese extract by Kjeldahl was 0.958. Concentrations of soluble tyrosine and soluble tryptophane were measured spectrophotometrically at optical densities of 270 and 290 mµ. Equations were developed by Vierordt's method of analysis of two component systems for this pair of wave lengths. Relationships between these compounds and percentage of soluble nitrogen in the cheese were linear and highly significant; the coefficient of correlation between soluble tyrosine and percentage of soluble nitrogen was 0.964; whereas, that between soluble tryptophane and percentage of soluble nitrogen was 0.886. Flavor intensity estimated in the 40 lots of cheese by professional judges showed a linear relationship to soluble tyrosine.
References
- Ultraviolet Absorption Spectra of Proteins and Amino Acids.Advances in Protein Chem. 1952; 7: 319
- The Relationship of the Amount of Tyramine and the Number of Streptococcus faecalis to the Intensity of Flavor in American Cheddar cheese.J. Dairy Sci. 1948; 31: 305
- The Spectrophotometric Determination of Tyrosine and Tryptophan in Proteins.Biochem. J. 1946; 40: 628
- Fortgesetzte spektralphotometrische und Chemische blutgruppenuntersnchung.Z. 1937; 290: 24
- Ultraviolet Absorption of Genuine and Hydrolyzed Protein.Nature. 1939; 143: 118
- A Study of Conditions for Kjeldahl Determination of Nitrogen in Proteins.J. Biol. Chem. 1948; 176: 1401
- Spectrophotometry of Proteins.Biochem. J. 1936; 30: 1795
- Adaptation of Tyrosine Method in Routine Cheese Analysis.J. Dairy Sci. 1950; 33: 438
- Milk Proteins.Advances in Protein Chem. 1949; 5: 201
Mogensen,M. T. S. Bestemmelse af ostens proteolytiske spaltnings-grad med saerligt henblik paa formoltitreringen. Medd. Statens Mejeriforsök, No. 21. 1948.
- Colorimetric Gauging of the Tryptophan and Tyrosine Content of Cheese and Its Use for Rapid Determination of the Degree of Ripening of Cheese.Proc. 12th Intern. Dairy Congr. 1949; 2: 849
- A Bacterial Enzymatic Method for Determining Tyrosine in Cheese.J. Dairy Sci. 1955; 38: 941
- Tyrosine in Cheddar Cheese.J. Dairy Sci. 1955; 38: 950
- Statistical Methods.5th ed. The Iowa State College Press, Ames, Iowa1956
- The Influence of the pH upon the Ultraviolet Absorption Spectra of Certain Cyclic Compounds.J. Phys. Chem. 1925; 29: 1477
- The Practice of Absorption Spectrophotometry with Hilger Instruments.2nd ed. A. Hilger, Ltd., London, England1934
Article info
Publication history
Received:
September 15,
1958
Identification
Copyright
© 1959 American Dairy Science Association. Published by Elsevier Inc.
User license
Elsevier user license | How you can reuse 
Elsevier's open access license policy
Elsevier user license
Permitted
For non-commercial purposes:
- Read, print & download
- Text & data mine
- Translate the article
Not Permitted
- Reuse portions or extracts from the article in other works
- Redistribute or republish the final article
- Sell or re-use for commercial purposes
Elsevier's open access license policy
