Dual modification of Sago starch: effects of sequence and levels of STMP: STPP and propylene oxide

Kong, Si Mun (2009) Dual modification of Sago starch: effects of sequence and levels of STMP: STPP and propylene oxide. Universiti Malaysia Sabah. (Unpublished)

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Abstract

An attempt was carried out by employing a 2x2x3 Factorial Design consisting of thirteen runs (inclusive of native), to study the effects of levels and modification sequence on physicochemical properties of hydroxypropylated (HP) and cross-linked (Cl) sago starches. The physicochemical properties include swelling, solubility, clarity, apparent viscosity, pasting and thermal properties. Somehow, cross-linking exhibited more pronounced effect on most of the responses studied as compared to hydroxypropylation. Swelling, solubility and clarity shared similar trends; reporting that modification sequence and concentration of cross-linking significantly influenced (p>0.05) these attributes; while increased concentrations of PO showed no significant (p>0.05) effect on swelling, solubility and clarity of paste. The coefficient correlation of cross-linking with these attributes were strongly negative (swelling power: r = - 0.905; solubility: r = - 0.878; and clarity: r = - 0.904). Apparently, these attributes affect the other physico-chemical properties. At fixed levels of 5:5, apparent and peak viscosity increased significantly (p<0.05) with increasing PO; due to the increased associative forces within starch granules which enhanced hydration. The correlation between hydration (solubility) and peak viscosity (r = 0.878) were proven to be positively related, hence supporting the above statement. However, at fixed concentration of PO, increasing S:S decreased both peak and apparent viscosity ; due to reinforced bonding between starch granules which subsequently decreased swelling and starch viscosity. Strong negative coefficient correlation were found between peak viscosity and degree of cross-linking (r = - 1.000). As modification sequence was reversed, viscosities of CL -HP starches decreased as compared to HP-CL starches; but only for samples with 0.01% S:S. The impact of reagent levels and modification sequence influenced the setback in a way similar to that of final viscosity but differed distinctly from breakdown. Although effect of levels significantly (p<0.05) influenced these attributes, no distinct trend was found as the PO concentration gradually increased or even when sequence was switched. Nevertheless, increment in S:S volumes significantly (p<0.05) decreased breakdown, while it increased setback and final viscosity of dual-modified starches. In terms of thermal behaViOUrs, sequence and levels of S:S did not have any significant (p<0.05) effect; but increasing amount of PO noticeably decreased (p<0.05) gelatinization transition temperature.

Item Type: Academic Exercise
Uncontrolled Keywords: Sago, Sago starches, Physio-chemical properties, Physio-chemical
Subjects: ?? TP248.13-248.65 ??
Divisions: SCHOOL > School of Food Science and Nutrition
Depositing User: Unnamed user with email storage.bpmlib@ums.edu.my
Date Deposited: 18 Jun 2012 08:55
Last Modified: 23 Oct 2017 04:29
URI: http://eprints.ums.edu.my/id/eprint/4381

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