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Physicochemical Characterization of Starches from Amaranthus Cruentus Grains
Author(s) -
Hoover R.,
Sinnott A. W.,
Perera C.
Publication year - 1998
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/(sici)1521-379x(199812)50:11/12<456::aid-star456>3.0.co;2-4
Subject(s) - amaranth , amylose , amaranthus cruentus , starch , cultivar , chemistry , granule (geology) , food science , amaranthaceae , botany , biology , paleontology
The physicochemical properties of starches isolated from three cultivars (Mexican, African and A200D) of Amaranth cruentus grains were studied. The yield of starch was in the range 29–38.3% on a whole grain basis. The starch granules were polygonal with smooth surfaces. The granule size was in the range 0.75–1.5 μm for all three cultivars. The free, bound and total starch lipids ranged from 0.05 (b 0.07%, from 0.16 to 0.28 and from 0.20 to 0.35%, respectively. The total amylose content ranged from 3.9 to 5.7% of which 10.3 to 15.8% were complexed by native lipid. The X‐ray pattern was of the “A” type. The intensities of the major diffraction patterns followed the order: Mexican > African > A200D. The swelling factor followed the order: A200D > African > Mexican. All three starches exhibited identical pasting temperatures. However, they differed with respect to the highest viscosity reached during the heating cycle (Mexican > A200D > African), viscosity at 95°C (Mexican > A200D > African), the extent of breakdown (African > A200D ∼ Mexican) in viscosity (during the holding cycle at 95°C) and setback (A200D > African > Mexican). The gelatinization temperature ranges were 72.2–91.0°C (Mexican), 69.8–84.1°C (African) and 69.0–83.6°C (A200D). The enthalpy of gelatinization (J g −1 ) were: 11.8 (Mexican) 12.3 (African) and 14.5 (A200D). The extent of acid hydrolysis (2.2 N HCl at 35°C) followed the order: A200D > African > Mexican. The susceptibility of the starches towards hydrolysis by porcine pancreatic α ‐amylase followed the order: African > A200D > Mexican. The freeze‐thaw stability followed the order: Mexican > African > A200D. The results of this study showed that bonding forces within the amorphous and crystalline regions are most pronounced in the Mexican cultivar.