THESIS

1.4 Scale up production of RS III by enzymatically debranching process
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The investigation of pullulanase enzyme concentration effects on degree
of pullulanase hydrolysis, β-amylolysis, degree of syneresis, resistant starch content
and physicochemical properties of RS III in the experiment 1.3 indicated that the
concentration of pullulanase enzyme with 12 unit/g of starch was an optimum level
for RS III formation. It had highest content of resistant starch content and little change
in physicochemical properties from the other treatments. Thus, the 12 unit/g starch of
pullulanase
enzyme debranching at 55°C for 16 hr of 15% high amylose rice starch
slurry preheated (121°C for 30 min) were selected for scale up (150 g of rice starch in
850g distilled water) to produced RS III in this experiment.
Comparative study on physiochemical properties of an experiment and the
larger- scale production of RS III formation
with three replications (Table 18) showed
not
significantly different (P≤0.05) among the two production scales. The viscosity of
the debranched product, degree of hydrolysis, degree of syneresis,
resistant starch
content,
water activity and production yield of the larger scale was close to the
experimental scale as following section.
1.4.1 Viscosity
The viscosity of the larger scale (1-lit starch solution)
formation of RS III measured at 100 rpm was lower than the experimental-scale (300-
ml starch solution) but not significant difference (P≥0.05) with an approximately
1,785.15 ± 13.18 and 1,790.50 ± 12.21 cP, respectively. The lower the viscosity, the
less was the tendency for any further spontaneous reduction with pullulanase
hydrolysis. Viscosity is the flow property of a material, or the resistance of the
material to flow under a mechanical stress
expressed in units of centipoises (cp)
(Elgun et al. 1998). Solutions with viscosity of less than 1,000 cp are freely flowing
liquids. Between
1,000 and 3,000 cp they have a thick, soup-like consistency, and at
higher viscosities, the gruels become progressively thicker (Hsu and Huang, 2000).