Modeling bleaching of tomato derivatives at subzero temperatures.
This work was addressed to obtain a predictive model of the rate of bleaching in tomato derivatives at subzero temperatures. To this aim, a tomato puree was freeze-dried and equilibrated at increasing solid fractions. The bleaching rate was assessed by measuring tomato color during storage for up to 18 months at temperatures from -30 to 0 degrees C. The temperature dependence of the tomato-bleaching rate was neither predictable using the Arrhenius equation nor simply related to tomato physical state. The lack of a clear Arrhenius relation was attributed to the occurrence of temperature-dependent phenomena, such as ice crystallization and oxygen solubility modifications, which strongly changed the local concentration of reactants. A modified Arrhenius equation predicting the tomato-bleaching rate in the entire temperature range was proposed. Tomato concentration, and hence its physical state, affected the temperature dependence of bleaching, modifying apparent activation energy and frequency factor of the modified Arrhenius equation. In light of these considerations, a mathematical model was set up and validated to accurately predict the tomato-bleaching rate on the basis of only its concentration and storage temperature.
Dipartimento di Scienze degli Alimenti, Università di Udine, via Marangoni 97, 33100 Udine, Italy. lara.manzocco@dsa.uniud.it
Lara
L
Manzocco
Sonia
S
Calligaris
Maria Cristina
MC
Nicoli
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005519:Food Preservation / Q000379:methods*; D005615:Freezing; D005638:Fruit / Q000737:chemistry; D018551:Solanum lycopersicum / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010860:Pigments, Biological / Q000737:chemistry*; D015203:Reproducibility of Results; D012995:Solubility; D013816:Thermodynamics; D013997:Time Factors
D010860:Pigments, Biological; D010100:Oxygen