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Carboxy distribution of low‐methoxy pectin deesterified in situ
Author(s) -
Tuerena Colin E.,
Taylor Andrew J.,
Mitchell John R.
Publication year - 1984
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740350718
Subject(s) - pectin , chemistry , affinities , orange (colour) , in situ , degree of polymerization , pectinesterase , chromatography , stereochemistry , food science , polymerization , organic chemistry , enzyme , pectinase , polymer
The distribution of free carboxy groups in a series of orange pectins deesterified in situ by enzymic and alkaline action has been measured. A sharp change in the average free carboxy block size of enzymically deesterified pectin at a degree of esterification of about 25% was found. At degrees of esterification below this value, a number of blocks of free carboxy groups with degrees of polymerisation greater than 30 were found, whereas at higher degrees of esterification blocks as large as this were virtually absent. This may be explained in terms of the action of two pectinesterase isoenzymes which have affinities for high and low methoxy pectins, respectively. This work provides an explanation for the sharp decrease in gelling performance found for treated orange peel in heat processed systems as the degree of esterification of pectin increases above 25%.