Molecular structure and gelatinization properties of barley and sorghum starches
2005
Hara, T.(Tokyo Bunka Junior Coll. (Japan)) | Takasaki, F. | Ohya, C.
In this study, the distribution of amylopectin chain length and gelatinization properties of starches prepared from barley (BS), sorghum (SS) and koshihikari rice (KS) were investigated. The average chain lengths defined by the sum of Fr.II and Fr.III values were 32.9 in BS and 31.7 in SS. These values were longer than that in KS (21.6). The contents of long chains with average lengths of 60 or more were 13.3 mol%, 6.7 mol% and 8.8 mol% in BS, SS and KS, respectively. Therefore, the long chain content in BS was higher and that in SS was lower than that in KS. The contents of short chains with average lengths from 10 to 20 in BS and KS were high. On the other hand, the short chain content in SS was less than 10. The distribution of amylopectin chain length was evaluated using Fr.III/Fr.II ratio. The Fr.III/Fr.II ratios were 3.93, 2.82 and 3.22 in BS, SS and KS, respectively. The swelling power and solubility of BS were higher than those of SS and KS. The swelling power and solubility of SS were respectively lower and higher than those of BS and KS. The maximum viscosity and breakdown, measured using a rapid viscoanalyzer, were the highest in BS among the three starches, and those of SS were the lowest. However, the final viscosity of SS was higher than the maximum viscosity.
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