Functional properties of resistant starch type-III from Metroxylon sagu as affected by processing conditions

Type III resistant starch (RS3) was produced from native sago starch using different processing conditions. Native sago starch contained 93.5% total starch, of which was 25.8% amylose and 67.7% amylopectin. A sample with the highest RS3 content (35.7%) was produced when the native sago starch was suspended in distilled water, gelatinised by autoclaving at 121°C for 1 h,followed by debranching with 20U pullulanase per g starch at 60°C for 24 h, autoclaved again at 121°C for 1 h before storage at 4°C for 24 h. The sago RS3 sample contained 54.0% amylose and 38.8% amylopectin. The powder had solubility,swelling power, water-holding and oil-holding capacity of 27.4%,2.8g/g,1.7g/g and 1.1g/g,respectively. Treatment of the sago RS3 with 0.5M HCl acid at 60°C for 24 h produced HCl-sago RS3 with 68.30% RS3 content. The solubility and swelling power of HCl-sago RS3 was 14.9% and 1.9g/g,respectively. Different processing conditions had significantly influenced the amount and properties of RS3 produced from sago starch.