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Turbidity and protein aggregation in whey protein beverages
Caitlin E LaClair1, Mark R Etzel
1Dept of Food Science, Univ of Wisconsin, Madison, WI 53706, USA.
Journal of Food Science
|November 10, 2009
Summary
Whey protein aggregation causes turbidity and sedimentation in acidic beverages. Storage temperature significantly accelerates this process, impacting beverage quality over time.
Area of Science:
- Food Science and Technology
- Protein Chemistry
- Colloid Science
Background:
- Heat-treated acidic whey protein beverages are prone to protein aggregation during storage.
- Protein aggregate formation leads to undesirable turbidity and sedimentation, affecting product quality.
- Understanding the kinetics of aggregation is crucial for stabilizing these products.
Purpose of the Study:
- To investigate the kinetics of protein aggregation in heat-treated acidic whey protein beverages.
- To determine the role of pre-formed aggregates in subsequent soluble protein deposition.
- To model the influence of storage temperature on turbidity and sedimentation.
Main Methods:
- A model acidic whey protein beverage (12.5 g/L, pH 4) was heat-treated and stored for 6 weeks at three different temperatures.
- Samples were analyzed for turbidity, soluble protein concentration, and protein aggregate formation.
- Comparison between untreated samples and those filtered to remove heat-induced aggregates.
Main Results:
- Turbidity increased and soluble protein decreased over storage, correlating with protein aggregate formation.
- Higher storage temperatures significantly accelerated the rate of aggregation and quality degradation.
- The loss of soluble protein followed first- and second-order kinetic models.
Conclusions:
- A slow protein aggregation process governs the rate of sediment and turbidity formation.
- Aggregates formed during heat treatment may act as nuclei for soluble protein deposition.
- Kinetic modeling allows prediction of whey protein aggregation based on concentration, time, and temperature.
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