Modelling the gelling behaviour of linseed polysaccharide: effect of salts and pH.

Susheelamma, N. S. and Chand, N. and Rajalakshmi, D. (1994) Modelling the gelling behaviour of linseed polysaccharide: effect of salts and pH. Journal of Texture Studies, 25 (4). 437-454, 18 ref..

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Abstract

The rheological properties of linseed polysaccharide gels in the presence of citric acid, calcium and magnesium carbonates were studied using a factorial design and the Herschel-Bulkley model. The yield stress and consistency index increased with the concentration of calcium and magnesium ions, while the flow behaviour index decreased, imparting stability to the gel. With citric acid, ac, and k reached a maxima and then decreased, while n increased after an initial dip. The effect of pH (3.4-9.3), sucrose (45-55%), and polysaccharide (0.6-0.8%) on rheological constants were modelled using polynomials where up to fifth power of pH was required. Ln(o-,), ln(k), and n were fitted to the standardised (normalised) forms of pH, In (sucrose) and In (polysaccharide) with multiple correlations of 0.95, 0.97 and 0.98, respectively. The two optima (with pH) were computed using Nelder and Mead's flexible polyhedral search method. Both required 55 % sucrose and 0.8% polysaccharide with pH of 4.3 and 7.3, respectively. The models at the two optima are discussed through 3-D graphs. The technological implications of the dual optima have been indicated. This is, probably, the first report where two optima, with pH, have been observed for a gel forming polysaccharide.

Item Type:	Article
Uncontrolled Keywords:	linseed polysaccharide, Herschel-Bulkley model, gelling
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 28 Polysaccharide Chemistry
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	08 May 2012 06:06
Last Modified:	30 Jun 2015 12:13
URI:	http://ir.cftri.res.in/id/eprint/4655

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