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Degradation kinetics of chlorophyll in peas as a function of pH
- Ryan-Stoneham, T., Tong, C.H.
- Journal of food science 2000 v.65 no.8 pp. 1296-1302
- peas, chlorophyll, degradation, pH, heat treatment, organic acids and salts, simulation models, temperature, mathematical models, prediction
- The kinetics of chlorophyll degradation in pea puree were determined in a specially designed reactor with on-line pH control capability. Without pH control, the pH of the pea puree decreased continuously with heating due to acid formation; the pH was maintained within +/-0.1 of the desired value with on-line pH control. Chlorophyll (both a and b) degradation followed the first-order reaction model. The temperature dependence of the rate constant was adequately modeled by the Arrhenius equation. The activation energy was independent of pH and was 17.5 kcal/mol and 17 kcal/mol for chlorophyll a and chlorophyll b, respectively. The degradation rate constant decreased log-linearly as the pH was increased. A mathematical model was developed to predict the chlorophyll concentrations as a function of time, temperature and pH.