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Characterisation of Jícama (Mexican Potato) ( Pachyrhizus erosus L. Urban) Starch From Taproots Grown in USA and Mexico
Author(s) -
Stevenson David. G.,
Jane Jaylin,
Inglett George E.
Publication year - 2007
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.200600596
Subject(s) - starch , amylopectin , amylose , chemistry , maize starch , molar mass , food science , viscosity , materials science , polymer , organic chemistry , composite material
Characteristics of starch extracted from roots of jícama ( Pachyrhizus erosus L. Urban) cultivated in Texas and two locations in Mexico were studied. Jícama starch granules were spherical or polygonal with diameters ranging from 1‐15 µm. Jícama starch exhibited C A ‐type X‐ray diffraction pattern, an apparent amylose content of 28.1% and absolute amylose content of 23.6%. Jícama amylopectin weight‐average molar mass ( M w ) was 3.9×10 8 g/mol and gyration radius ( R z ) was 363 nm. Average amylopectin branch chain‐length was short (DP 22.7). Onset gelatinisation temperature was very low (52.0°C) and enthalpy change was 15.1 J/g. Thermal transition of amylose‐lipid dissociation was not observed. Peak (282 RVU), final (221 RVU) and breakdown (137 RVU) viscosity of 8% jícama starch paste were high relative to other starches and pasting temperature was 72.3°C. Starch characteristics were similar among all three growing locations except M w , R z and pasting properties. High paste viscosity and low gelatinisation temperature could give jícama starch advantages in some industrial applications.