title: Effects of controlled-frequency moderate electric fields on pectin methylesterase and polygalacturonase activities in tomato homogenate.
abstract: The effect of controlled-frequency moderate electric field treatments on pectin methylesterase and polygalcturonase activities in tomato homogenate was investigated by subjecting identically treated control and electrically-treated samples to the same temperature history. Additionally, a model was developed for the motion of the enzyme molecules subjected to an electric field. Results show that the application of electric fields at a low field strength (0.4V/cm) constant temperature (65°C) has a statistically significant effect on pectin methylesterase activity, typically at or lower than 60 Hz. At higher frequencies, the effects are negligible. Molecular motion simulations suggest that the efficacy at low frequencies may be due to the amplitude of motion being of the order of the intermolecular distance for water. Higher frequencies result in small overall displacements due to rapid reversals in the direction of motion.
authors.affiliation: Department of Food, Agricultural and Biological Engineering, The Ohio State University, 590 Woody Hayes Drive, Columbus, OH 43210, United States.
authors.forename: Chaminda P
authors.initials: CP
authors.lastname: Samaranayake
authors.affiliation: Department of Food, Agricultural and Biological Engineering, The Ohio State University, 590 Woody Hayes Drive, Columbus, OH 43210, United States. Electronic address: sastry.2@osu.edu.
authors.forename: Sudhir K
authors.initials: SK
authors.lastname: Sastry
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D004560:Electricity; D018551:Solanum lycopersicum / Q000201:enzymology*; D011096:Polygalacturonase / Q000378:metabolism*; D013696:Temperature
chemical_list: D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase; D011096:Polygalacturonase
keywords: Electric field frequency; Food matrix; Moderate electric fields; Pectin methylesterase; Polygalcturonase