Starch Disorders: The Composition Of Wheat Starch

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Results and Discussion

3.1 Composition of wheat starch granules

The composition of starches and their separated A- and B- granules of two varieties are shown in Table 1. Amylose content of starches lies between 16.96 -24.69. The B-granules of the both varieties showed the lower value of amylose content while A- granules attributed to the high amylopectin to amylose ratio. Swelling power results the ability of starch to hydrate in specific cooking and heating process (90 °C/ 30 min.). The variation in swelling power of the starch and starch granules is due to change in strength in the bond forces with the granules (Leach et al.). Starch amylose content and granular properties affects the swelling power of the starches (Singh & Singh 2001).
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1 (a & b), and pasting parameters are summarized in table 2. The pasting properties from both wheat varieties showed significant differences. For C-306, the unfractionated starch showed a higher peak, through, breakdown, final, and setback viscosities than the WH-147 unfractionated starch, while the WH-147 unfractionated starch had higher pasting temperature than the C-306 unfractionated starch. A-granules showed a higher peak, trough, breakdown, final, and setback viscosities than the B-granules starch, while the B-granule starch had higher pasting temperature than the A- granule starch counterparts (Table 2) for both the varieties. Though, the B-granules were characterized with the higher peak time in comparison to the A- granules, but the difference was not so significant. Similar results have been reported by Sahlstrom et al. (2003) and Jane (2007). Variations in the RVA parameters for both the varieties and in granules may be due to their difference in morphology and amylose …show more content…
The high pasting temperature of starches indicates a higher resistance to swelling and rupture (Li et al. 2011). During the cooling stage, glucan chains of starch molecules entangled to each other forming a gel and increase in the paste viscosity (Fig.1). The setback viscosity (difference between peak and final viscosity) is exhibited due to recrystallization of amylose molecules in the gel, which is the measure of the gelling ability or retrogradation ability of starches (Marie et al. 2004). Setback viscosity was higher for A- granules and B- granules in C-306 and WH- 147 respectively (table). This may be attributed due to the differences in amylose contents of the two

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