Clarification of juice by thermolabile valencia pectinmethylesterase is accelerated by cations.
Pectinmethylesterase (PME) was isolated from Valencia orange pulp and added to reconstituted juice at 1.2 units/mL of juice in the presence or absence of cations at 4.2 or 16.7 mM. The percent transmittance (%T) of control juices with no added PME or cation did not clarify. The %T of juices with added PME and added cation was 45-55% by the second day. Increases in the average particle size was observed with PME- or cation-added juices and preceded increases in %T. Most likely, cations displaced PME from an inactive pectin substrate complex and increased clarification. PME, in the absence of cations, increased particle size but did not affect %T, suggesting a direct interaction of PME with cloud particles.
Wicker
L
L
Department of Food Science and Technology, Physical Properties Group, University of Georgia, Athens, Georgia 30602, USA. lwicker@arches.uga.edu
Ackerley
J L
JL
Corredig
M
M
D001628:Beverages; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002412:Cations / Q000494:pharmacology*; D002957:Citrus / Q000201:enzymology*; D004795:Enzyme Stability; D005511:Food Handling; D005638:Fruit / Q000201:enzymology*; D006358:Hot Temperature; D010316:Particle Size
D002412:Cations; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase