Publication no. C-2002-0204-06R |  VIEW ARTICLE

Structural and Functional Characteristics of Selected Soft Wheat Starches (1).

Célia M. L. Franco (2), Kit-Sum Wong (3), Sang-ho Yoo (3), and Jay-lin Jane (3,4). (1) Journal Paper No. J-18915 of the Iowa Agriculture and Home Economic Experiment Station, Ames, IA. Project No. 3258. (2) Dept of Food Engineering and Technology, Universidade Estadual Paulista (IBILCE/UNESP), São José do Rio Preto, SP, Brazil, 15054-000. (3) Dept of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011. (4) Corresponding author. E-mail: <jjane@iastate.edu> Cereal Chem. 79(2):243-248. Accepted January 15, 2002. Copyright 2002 American Association of Cereal Chemists, Inc.

Starches from eight soft wheat samples (two parent lines and six offspring) were isolated; relationships between their structures and properties were examined. Branch chain-length distributions of amylopectins were determined by using high-performance anion exchange chromatography equipped with an amyloglucosidase reactor and a pulsed amperometric detector (HPAEC-ENZ-PAD). Results showed that the average chain length of the eight samples varied at DP 25.6-26.9. Starch samples of lines 02, 60, 63, 95, and 114 consisted of amylopectins with more long chains (DP > 37) and longer average chain length (DP 26.2-26.9) than that of other samples. These starch samples of longer branch chain length displayed higher gelatinization temperatures (55.3-56.5°C) than that of other samples (54.4-54.9°C) and higher peak viscosity (110-131 RVU) and lower pasting temperature (86.3-87.6°C) than others (83-100 RVU and 88.2-88.9°C, respectively). The M(w) of amylopectins, determined by using high-performance size exclusion chromatography equipped with multiangle laser-light scattering and refractive index detectors (HPSEC-MALLS-RI), were similar for all samples (6.17 × 10(^8) to 6.97 × 10(^8)). There were no significant differences in amylose and phosphorus contents between samples. These results indicated that physical properties of wheat starch were affected by the branch-chain length of amylopectin.