Simultaneous modelling of the thermal degradation kinetics of pectin methylesterase in lettuce (Lactuca sativa L.) and carrot (Daucus carota L.) extracts: analysis of seasonal variation and tissue type.
The thermal degradation kinetics of pectin methylesterase (PME) from carrot and lettuce were studied. Fresh extracts were exposed to temperatures from 55 to 70 degrees C until the enzyme was inactivated. A model based on the presence of two forms of the enzyme, one active and one non-active, is proposed. The natural variability of the PME activity was taken into the model in the form of normally distributed random effects. The common model parameters obtained (cleavage constant (0.0395+/-0.0062 s(-1)), degradation constant (0.556+/-0.112 s(-1)), cleavage energy of activation (469+/-23 kJ mol(-1)) and degradation energy of activation (488+/-18 kJ mol(-1))) show that the PME degradation kinetics of the two vegetables can be explained with a single set of parameters.
Rico
Daniel
D
Postharvest Technology Unit, Dublin Institute of Technology (DIT), School of Food Science and Environmental Health, Faculty of Tourism and Food, Ireland. daniel.rico@dit.ie
Martín-Diana
Ana B
AB
Barry-Ryan
Catherine
C
Henehan
Gary T M
GT
Frías
Jesús M
JM
D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000378:metabolism*; D018552:Daucus carota / Q000201:enzymology*; D006358:Hot Temperature; D007700:Kinetics; D018545:Lactuca / Q000201:enzymology*; D008969:Molecular Sequence Data; D010936:Plant Extracts / Q000737:chemistry; D012621:Seasons; D017386:Sequence Homology, Amino Acid
D010936:Plant Extracts; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase