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DEMETHYLATION OF PECTIN USING ACID AND AMMONIA
Author(s) -
KIM W. J.,
SMIT C. J. B.,
RAO V. N. M.
Publication year - 1978
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1978.tb09739.x
Subject(s) - chemistry , ammonia , amide , pectin , hydrochloric acid , demethylation , organic chemistry , inorganic chemistry , nuclear chemistry , biochemistry , gene expression , dna methylation , gene
The kinetics of deesterification of high‐ester citrus pectin, using acid, ammonia, or a treatment with acid followed by ammonia in isopropanol was studied with respect to the changes in methyl ester groups, molecular weight, and the formation of acid amide groups. It was found that: (1) Higher concentrations of acid or ammonia at low temperature resulted in less depolymerization for a certain decrease in ester groups; (2) The conversion of methoxyl groups to acid amide groups approached unity as temperature was lowered and ammonia concentration increased. A linear relationship between the increase in amide content and the decrease in esterification was found; (3) In treatments using hydrochloric acid followed by ammonia, a long acid treatment and a short ammonia treatment resulted in a maximum retention of apparent molecular weight. However, this treatment gave a smaller number of acid amide groups in the final product. Depending on the selection of ammonia concentration and temperature, a wide range of acid amide levels was possible. It was also possible to predict the conditions needed for deesterification to give certain apparent molecular weights and ratios of amide levels to ester levels.