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Experiments on the heat-induced salt balance changes in cow's milk
Y Pouliot1, M Boulet, P Paquin
1Département de Sciences et Technologie des Aliments, Université Laval, Québec, Canada.
The Journal of Dairy Research
|January 1, 1989
Summary
Heating milk causes changes in its salt balance, with calcium and phosphorus decreasing significantly as temperature rises. This study investigated heat-induced salt precipitation in milk serum using ultrafiltration.
Area of Science:
- Dairy Science
- Food Chemistry
- Physical Chemistry
Background:
- Milk's colloidal phase and serum interact, influencing its stability.
- Heat treatment is crucial in milk processing but affects its composition.
- Understanding salt balance changes is key to controlling milk properties.
Purpose of the Study:
- To investigate heat-induced alterations in salt distribution between milk's colloidal phase and serum.
- To quantify the impact of varying temperatures on mineral and citrate concentrations in milk serum.
- To explore the mechanism behind heat-induced salt precipitation in milk.
Main Methods:
- Utilized ultrafiltration with a hollow fiber cartridge and heat exchanger to isolate milk permeate at different temperatures.
- Heated milk samples from 4°C to 20°C, 40°C, 60°C, 80°C, and 90°C.
- Determined the concentrations of calcium (Ca), phosphorus (P), magnesium (Mg), and citrate in the collected permeates.
Main Results:
- Calcium and phosphorus concentrations in milk permeate decreased proportionally with increasing temperature.
- Magnesium and citrate showed smaller concentration losses compared to calcium and phosphorus.
- A rapid initial decrease in salt concentration was observed within seconds, followed by a slower decline.
Conclusions:
- Heat treatment significantly impacts the salt balance in milk, leading to precipitation.
- The observed changes suggest a two-stage precipitation mechanism, likely involving dicalcium phosphate and tricalcium citrate.
- Findings provide insights into the chemical changes during milk heating, relevant for dairy processing and stability.
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