Preparation and Characterisation of Cross-Linked Sago Starch Phosphates
This project was conducted to study the production of cross-linked sago starch phosphate and to characterise the material produced. Sago starch was phosphorylated at various pHs (from 6 to 11) under a range of phosphate salt concentrations (sodium tripolyphosphate [STPP] [1 to 9%] and sodium tri...
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| Format: | Thesis |
| Language: | English English |
| Published: |
1998
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/9728/1/FSMB_1998_18_A.pdf |
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| Summary: | This project was conducted to study the production of cross-linked sago
starch phosphate and to characterise the material produced. Sago starch was
phosphorylated at various pHs (from 6 to 11) under a range of phosphate salt
concentrations (sodium tripolyphosphate [STPP] [1 to 9%] and sodium
trimetaphosphate [STMP] [1 to 4%]) and in the presence of various sodium sulfate
concentrations (1 to 9%). The phosphorylation was carried out for 40 to 80 mins at
temperatures varying from 27 to 50°C and heating time from 0.5 to 3 hrs at
temperatures between 100 to 160°C. It was observed that the reaction pH and
concentration of phosphate salts played a significant effect on the phosphorus (P)
content, pasting profile, and paste clarity of the sago starch phosphates produced.
The phosphorus content was found to increase as the pH and concentration of
phosphate salts were increased under all conditions. However, the phosphorus
contents were found to be below the standard (STPP [0.4%], STMP [0.04%], and a
mixture of STPP and STMP [0.4%]), except when the concentration of STMP was
above 1%. The pasting profile showed that at pH 9.5, treatment of sago starch with a mixture of 5% STPP and 2% STMP yielded the best cross-linked sago starch
phosphate where it showed the lowest hot paste viscosity and the highest cold paste
viscosity. Paste clarity measurements of the phosphorylated starches indicated that
cross-linking had accelerated rapidly with STMP above pH 8, with STPP above pH
9, and with a mixture of the two above pH 6. Paste clarity measurements also
showed that cross-linking began to accelerate at 5% and below STPP, and 2% and
below STMP when sago starch was phosphorylated at pH 11 and 8, respectively.
Judging from the paste properties, phosphorylation of sago starch at 27°C for 1 hr
with a mixture of 5% STPP and 2% STMP at pH 9.5 in the presence of 5% sodium
sulfate and then heating at 130°C for 2 hr is recommended. Cross-linked sago starch
phosphate and commercial cross-linked waxy com starch (Mazaca 3543X and
3544X) showed similar pasting profile. However, cross-linked sago starch phosphate
had higher degree of phosphorylation (Phosphorus content), degree of substitution,
swelling power and solubility, paste clarity and gel strength. The water holding
capacity and sediment volumes were similar to one of the cross-linked waxy com
starches (Mazaca 3544X). Morphology studies showed that these modified starches
retained their granule shape with minimal degree of starch damage. |
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