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Effect of milk solids concentration on the pH, soluble calcium and soluble phosphate levels of milk during heating

Effect of milk solids concentration on the pH, soluble calcium and soluble phosphate levels of... When milk is processed to dairy products, the concentration of the milk and the temperature/time combinations to which the milk is exposed can be varied. For example, large differences in milk concentrations and temperature/time combinations are used in the manufacture of milk powder or the various concentrated liquid milk products. Although the milk salts, particularly the concentrations and equilibrium states of calcium and inorganic phosphate, are considered to be important in the stability and functionality of dairy products, there have been few studies on the mineral balance in concentrated milk systems and how this is affected by temperature changes. The objective of this study was to examine the effect of milk concentration (9.6–38.4% w/w total solids), temperature (20–80 °C) and time (0–60 min) on the pH and the concentrations of soluble calcium (Casol) and soluble inorganic phosphate (Psol). At any given temperature, the level of Casol and Psol, as mmol·kg−1, increased and the pH decreased as the milk concentration was increased. However, when measured as a percentage of the total, the level of Casol and Psol decreased as the milk concentration was increased. At any given milk concentration, the level of Casol, Psol and milk pH decreased within the first few minutes of heating, with little further change at longer heating times. For milk samples at each concentration, there was a strong correlation between the final Casol and the final Psol at all temperatures. At any particular milk concentration, there was a strong correlation between the final milk pH and the final Casol or the final Psol levels. These results indicate that substantial decreases in milk pH, Casol and Psol can occur at the temperatures milk will experience in common commercial processes, and the extent of the changes will be dependent on the milk concentration and the processing conditions. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Dairy Science & Technology Springer Journals

Effect of milk solids concentration on the pH, soluble calcium and soluble phosphate levels of milk during heating

Dairy Science & Technology , Volume 89 (5) – May 21, 2011

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Publisher
Springer Journals
Copyright
Copyright © 2009 by Springer S+B Media B.V.
Subject
Chemistry; Food Science; Agriculture; Microbiology
ISSN
1958-5586
eISSN
1958-5594
DOI
10.1051/dst/2009026
Publisher site
See Article on Publisher Site

Abstract

When milk is processed to dairy products, the concentration of the milk and the temperature/time combinations to which the milk is exposed can be varied. For example, large differences in milk concentrations and temperature/time combinations are used in the manufacture of milk powder or the various concentrated liquid milk products. Although the milk salts, particularly the concentrations and equilibrium states of calcium and inorganic phosphate, are considered to be important in the stability and functionality of dairy products, there have been few studies on the mineral balance in concentrated milk systems and how this is affected by temperature changes. The objective of this study was to examine the effect of milk concentration (9.6–38.4% w/w total solids), temperature (20–80 °C) and time (0–60 min) on the pH and the concentrations of soluble calcium (Casol) and soluble inorganic phosphate (Psol). At any given temperature, the level of Casol and Psol, as mmol·kg−1, increased and the pH decreased as the milk concentration was increased. However, when measured as a percentage of the total, the level of Casol and Psol decreased as the milk concentration was increased. At any given milk concentration, the level of Casol, Psol and milk pH decreased within the first few minutes of heating, with little further change at longer heating times. For milk samples at each concentration, there was a strong correlation between the final Casol and the final Psol at all temperatures. At any particular milk concentration, there was a strong correlation between the final milk pH and the final Casol or the final Psol levels. These results indicate that substantial decreases in milk pH, Casol and Psol can occur at the temperatures milk will experience in common commercial processes, and the extent of the changes will be dependent on the milk concentration and the processing conditions.

Journal

Dairy Science & TechnologySpringer Journals

Published: May 21, 2011

References