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Thermodynamic aspects of the gelatinization and swelling of crosslinked starch
Author(s) -
Hollinger G.,
Kuniak L.,
Marchessault R. H.,
Marchessault R. H.
Publication year - 1974
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1974.360130504
Subject(s) - swelling , epichlorohydrin , chemistry , starch , differential scanning calorimetry , chemical engineering , polymer chemistry , starch gelatinization , enthalpy , swelling capacity , organic chemistry , thermodynamics , physics , engineering
Samples of epichlorohydrin crosslinked potato starch were prepared by using a high ratio of starch to water and alkali concentration below the gelatinization level. This yielded crosslinked samples that were partially crystalline, and where the number of crosslinks could be varied between 1 and 20 crosslinks per 100 anhydroglucose units. The degree of swelling varied regularly with degree of crosslinking, and the molecular weight between crosslinks M c as derived from swelling data in a good swelling agent compared favorably with M c derived from chemical analysis. From the heat of gelatinization of the crosslinked starches, as observed in a differential scanning calorimeter, for gelatinization in glycerol, water, and dimethylsulfoxide, a model for the gel state of the crosslinked starch is proposed. It is concluded that the entropy of melting is the determining factor in establishing the temperature of gelatinization.