Effect of pH on chlorophyll degradation and colour loss in blanched green peas
2007
Koca, N. | Karadeniz, F. | Burdurlu, H.S.
Effect of pH on the chlorophyll degradation and visual green colour loss in blanched green peas were studied at 70, 80, 90 and 100 °C in buffered solutions of pH 5.5, 6.5 and 7.5. The degradation of chlorophylls a and b followed a first-order reaction and the temperature-dependence of these reactions was modelled by the Arrhenius equation. The activation energies ranged from 4.80 ± 0.91 to 14.0 ± 0.71 kcal mol-1 for chlorophyll a and from 6.84 ± 0.29 to 11.0 ± 1.06 for chlorophyll b with varying pH values. The visual green colour degradation, as represented by the change of the -a (greenness), the ratio -a/b and hue (h) values measured by tristimulus colorimeter, also followed a first-order reaction. Activation energies for -a values ranged from 8.13 ± 0.71 to 12.0 ± 1.07 kcal mol-1, and for -a/b values ranged from 8.77 ± 1.34 to 12.0 ± 1.07 kcal mol-1 with varying pH values at 70, 80, 90 and 100 °C.
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