THESIS

essentially linear polymer of α-(1,4)-linked D-glucopyranosyl units with slightly
branched of α- (1,6)-linked (Ghampagne, 1996). Rice starch amylose have DPn value
of 920 – 1110, CL of 250-370 and β-amylolysis limits of 73 -84% (Takeda et al.
1986). Rice starch amylopectin consists of α-(1,4)-linked D-glucosyl chains and
highly branched with 5 - 6% of α-(1,6)-bonds (Buleon et al. 1998). It has a DPn of
8,200-12,800, CL values of 19 -23 and β-amylolysis limits of 49 - 59% (Takeda et al.
1986).
Table 13 Chemical composition and fine structural of the native high amylose rice
starch
Chemical composition Native high amylose rice starch
(% wwb) a
Moisture content 13.01 ± 1.05
Fat 0.91 ± 0.28
Ash 0.82 ± 0.34
Protein 1.18 ± 0.06
Total carbohydrate 83.78 ± 0.52
Total starch (dwb) 95.21 ± 1.20
Amylose content 32.10 ± 0.67
Amylopectin 67.93 ± 0.57
β-amylolysis limits 62.48 ± 2.49
pH 5.50 ± 0.65
a Values are means of triplicate measurements ± standard deviations.
1.1.2 Granular structure
Scanning electron micrograph (magnification at 2500x and
6000x) of native commercial high amylose rice starch granules are shown in Figure
13. Native commercial high amylose rice starch granules were observed to be
90