Pheophytins chlorophyll conversion

Studies of chlorophyll degradation in heated broccoli juices over the 80 to 120°C range revealed that chlorophylls degrade first to their respective pheophytins and then to other degradation products in what can therefore be described as a two-step process. Both chlorophyll and pheophytin conversions followed a first-order kinetics, but chlorophyll a was more heat sensitive and degraded at a rate approximately twice that of chlorophyll This feature had been observed by other authors. Temperature dependence of the degradation rate could adequately be described by the Arrhenius equation. ... 

HAISMAN D R and Clarke M W (1975), The interfacial factor in the heat-induced conversion of chlorophyll to pheophytin in green leaves , J Sci Food Agric, 26, 1111-1126. 

Volkov AG, Gugeshashvili MI, Zelent B et al. Light energy conversion with chlorophyll a and pheophytin a monolayers at the optically transparent Sn02 electrode Artificial photosynthesis. 

Water activity has been shown to have a definite influence on the rate of degradation of chlorophyll in freeze-dried, blanched spinach puree [73]. At 37°C and an higher than 0.32, the most important mechanism of chlorophyll degradation was conversion to pheophytin. At lower than 0.32, the rate of pheophytin formation in spinach was low. The rate of chlorophyll-a transformation was 2.5 times faster than chlorophyll-. The study of the degradation of chlorophyll as a function of a . pH, and temperature in a spinach system... 

MODEL COMPOUND STUDIES OF PIGMENTS INVOLVED IN PHOTOSYNTHETIC ENERGY CONVERSION INFRARED (IR)-SPECTRO-ELECTROCHEMISTRY OF CHLOROPHYLLS AND PHEOPHYTINS... 

A change in color occurs during storage of dried vegetables, its extent increases with increasing water content. The conversion of chlorophylls to pheophytins continues in blanched vegeta-... 

During the firing step of tea processing, there is an initial rise in enzyme activity (10-15% of the theaflavins are formed during the first 10 min), then aU the enzymes are inactivated. Conversion of chlorophyll into pheophytin is involved in reactions leading to the black color of tea. A prerequisite for these reactions is high temperature... 

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