Research Article
Thermodynamics of Heat Inactivation of Aeromonas hydrophila in Soymilk of Varying Initial pH and Sugar Levels
Evelyn Mnguchivir Tersoo-Abiem*
,
Charles Chukwuma Ariahu,
Micheal Agba Igyor
Issue:
Volume 8, Issue 2, December 2024
Pages:
16-25
Received:
13 May 2024
Accepted:
3 June 2024
Published:
3 July 2024
Abstract: The thermodynamics of thermal inactivation of Aeromonas hydrophila in soymilk of varying pH (6.0-7.0) and sugar concentration (0-10%) were studied at a temperature of 50-65°C using kinetic parameters generated through the Classical thermobacteriology assumption of a log-linear relationship between A. hydrophila survivors and heating time. The activation enthalpy (ΔH#), activation entropy (ΔS#), activation energy (Ea) and frequency factor (Ko) for thermal inactivation of A. hydrophila in the soymilk samples were also obtained. Thermal inactivation of the organism followed first order reaction kinetics. The heat destruction rate constant (k) decreased with increase in heating temperature. The activation energy ranged from 210.98 to 215.28 kJ/mol increasing with decrease in pH and increase in sugar concentration of soymilk. The isokinetic temperature (TC) obtained varied from 55.95 to 56.62°C with inactivation of A. hydrophila exhibiting true compensation effect, with a Gibbs free energy of 82.86 kJ/mol. A combination of temperature, pH and sucrose significantly influenced inactivation of A. hydrophila in soymilk, following a similar mechanism being driven by entropy. Optimum safety from A. hydrophila can be achieved through application of multifactorial hurdles in soymilk processing. The thermodynamic data obtained will be useful to optimize thermal processing conditions for soymilk targeting A. hydrophila.
Abstract: The thermodynamics of thermal inactivation of Aeromonas hydrophila in soymilk of varying pH (6.0-7.0) and sugar concentration (0-10%) were studied at a temperature of 50-65°C using kinetic parameters generated through the Classical thermobacteriology assumption of a log-linear relationship between A. hydrophila survivors and heating time. The activ...
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