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Modeling bleaching of tomato derivatives at subzero temperatures
Lara Manzocco1, Sonia Calligaris, Maria Cristina Nicoli
1Dipartimento di Scienze degli Alimenti, Università di Udine, via Marangoni 97, 33100 Udine, Italy. lara.manzocco@dsa.uniud.it
Journal of Agricultural and Food Chemistry
|February 16, 2006
Summary
A new model predicts tomato bleaching rates at freezing temperatures. This model accounts for tomato concentration and storage temperature, improving predictions beyond the standard Arrhenius equation.
Area of Science:
- Food Science
- Chemical Engineering
- Physical Chemistry
Background:
- Color degradation (bleaching) in tomato products during frozen storage is a significant quality issue.
- Traditional models like the Arrhenius equation often fail to accurately predict bleaching rates at subzero temperatures due to complex physical and chemical changes.
Purpose of the Study:
- To develop a predictive model for the rate of bleaching in tomato derivatives stored at subzero temperatures (-30 to 0°C).
- To investigate the influence of tomato concentration and physical state on the temperature dependence of the bleaching rate.
Main Methods:
- Freeze-drying tomato puree and equilibrating it at various solid fractions.
- Monitoring tomato color changes over 18 months of storage at controlled subzero temperatures.
- Analyzing the temperature dependence of bleaching rates and developing a modified Arrhenius equation.
Main Results:
- The bleaching rate's temperature dependence was not accurately described by the standard Arrhenius equation.
- Phenomena like ice crystallization and altered oxygen solubility complicated the reaction kinetics.
- A modified Arrhenius equation, incorporating tomato concentration, successfully predicted bleaching rates across the tested temperature range.
Conclusions:
- Tomato concentration significantly impacts the temperature dependence of bleaching, altering kinetic parameters.
- A validated mathematical model using concentration and storage temperature can accurately predict tomato bleaching rates under freezing conditions.
- This research provides a more robust tool for predicting the shelf-life and quality of frozen tomato products.
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