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Physicochemical Properties of Sweet Potato Starches
Author(s) -
Takeda Y.,
Tokunaga N.,
Takeda C.,
Hizukuri S.
Publication year - 1986
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19860381006
Subject(s) - amylopectin , chemistry , amylose , degree of polymerization , starch , hydrolysis , food science , polymerization , phosphorus , organic chemistry , polymer
The physicochemical properties of the starches from three varieties of sweet potatoes were investigated. The crystalline structures of Koganesengan and Minamiyutaka starches were of the A type and that of Norin‐2 starch was of the Ca type. Their amylograms showed pasting temperatures of 73–75°C and maximum viscosities of 500–580 BU. 3‐Methyl‐1‐butanol lowered their pasting temperatures without altering their maximum viscosities. The amylose and organic phosphorus contents of the starches were 17.2–19.0% and 117–139 ppm, respectively. The amyloses comprised branched molecules of average degree of polymerization 3400–4400 with 10–13 chains on average and were hydrolyzed 72–73% by β‐amylase. The main amylopectins had average chain lengths of 21–22, β‐amylolysis limits of 55–56% and organic phosphorus contents of 117–144 ppm, of which 75–81% was attached to C–6 of the glucose residue and the remainder to C–3. Another type of amylopectin (10–15% of the starch), which had higher iodine affinity, was isolated.