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Aspartame degradation as a function of "water activity"
1Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108.
Advances in Experimental Medicine and Biology
|January 1, 1991
Summary
Aspartame degradation accelerates with increasing water activity (aw) and temperature, but is unaffected by glucose. Actual pH in condensed phases differs from initial pH, shifting optimal degradation rates.
Area of Science:
- Food Chemistry
- Chemical Kinetics
- Nutritional Science
Background:
- Aspartame is widely used in food products.
- Understanding aspartame degradation is crucial for food stability and safety.
Purpose of the Study:
- To evaluate aspartame degradation kinetics.
- To determine the influence of water activity (aw), pH, and temperature on aspartame stability.
Main Methods:
- Aspartame degradation was studied in model systems.
- Kinetics were analyzed across varying initial pH, temperature, and water activity (aw) levels.
Main Results:
- Degradation rate increased 30-80% per 0.1 unit increase in aw (0.3-0.7 range).
- Oil increased degradation at high aw; glucose had no effect.
- Activation energies decreased with increasing aw.
- Actual condensed-phase pH differed from initial pH, altering degradation rate optima.
Conclusions:
- Water activity is a key factor influencing aspartame stability in foods.
- The study highlights the importance of considering actual, rather than initial, pH for predicting aspartame degradation.