Effect of temperature and/or pressure on tomato pectinesterase activity.
The activity of tomato pectinesterase (PE) was studied as a function of pressure (0.1-900 MPa) and temperature (20-75 degrees C). Tomato PE was rather heat labile at atmospheric pressure (inactivation in the temperature domain 57-65 degrees C), but it was very pressure resistant. Even at 900 MPa and 60 degrees C the inactivation was slower as compared to the same treatment at atmospheric pressure. At atmospheric pressure, optimal catalytic activity of PE was found at neutral pH and a temperature of 55 degrees C. Increasing pressure up to 300 MPa increased the enzyme activity as compared to atmospheric pressure. A maximal enzyme activity was found at 100-200 MPa combined with a temperature of 60-65 degrees C. The presence of Ca(2+) ions (60 mM) decreased the enzyme activity at atmospheric pressure in the temperature range 45-60 degrees C but increased enzyme activity at elevated pressure (up to 300 MPa). Maximal enzyme activity in the presence of Ca(2+) ions was noted at 200-300 MPa in combination with a temperature of 65-70 degrees C.
Van Den Broeck
I
I
Department of Food and Microbial Technology, Laboratory of Food Technology, Faculty of Agricultural and Applied Biological Sciences, Katholieke Universiteit Leuven, Kardinaal Mercierlaan 92, B-3001 Heverlee, Belgium.
Ludikhuyze
L R
LR
Van Loey
A M
AM
Hendrickx
M E
ME
D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000201:enzymology*; D011312:Pressure; D013696:Temperature
D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase