Thermal Chlorophyll Degradation Kinetics of Mint Leaves Puree |
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| Authors: | S. Gaur B.C. Sarkar J. Ahmed |
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| Affiliation: | 1. Department of Biotechnology &2. Environmental Sciences , Thapar Institute of Engineering and Technology , Patiala, Punjab, India;3. Department of Food Technology , Sant Longowal Institute of Engineering &4. Technology , Longowal, India;5. Department of Food Science and Agricultural Chemistry, Macdonald Campus of Ste-Anne de Bellevue, Quebec H9X 3V9 , McGill University , Canada |
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| Abstract: | Thermal degradation kinetics of chlorophyll ‘a’, ‘b’ and total chlorophyll in mint leaves puree were investigated as function of pH (4.5–8.5) and processing temperature (80–145°C), respectively. Mint puree was processed at 80°to 100°C at pH 4.5, while that at pH 5.5 to 8.5 was processed at 105°to 145°C. Chlorophyll degradation followed the first order reaction kinetics. Good agreement was found between estimated and experimental chlorophyll retention in all cases (R2 > 0.86; MRQE < 0.27). Activation energies ranged from 6.45 to 47.67 kJ/mol. Reaction rate and activation energy data indicated that chlorophylls were more stable at alkaline pH. Transition state theory was applied to estimate the enthalpy, entropy and Gibbs free energy of activation. Enthalpy (ΔH#) ranged from 3.14 to 44.66 kJ/mol, while entropy (ΔS#) ranged from ?0.157 to ?0.266 kJ/(mol K). The overall free energy change was 105.76 kJ/mol. Results indicated that, the compensation effect did not exist for chlorophyll degradation in mint puree during thermal processing. |
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| Keywords: | Chlorophyll Thermal processing pH Kinetics Compensation |
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