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Influence of Fructose and Sucrose on Small and Large Deformation Rheological Behaviour of Heated Amioca Starch Dispersions
Department of Food Science and Technology, Cornell University-Geneva, Geneva, NY 14456-0462, USAmar2{at}cornell.edu Effect of sucrose or fructose on the rheological behaviour of gelatinized 5% w/w amioca starch dispersions (GSDs), was studied by small and large deformation rheological techniques. Storage (G0) and loss (G00) moduli as a function of angular frequency (o), and shear stress (s) as a function of shear rate (_) data were obtained on GSDs with: 0, 30 and 60% w/w sugars. Magnitudes of HerschelBulkley yield stress (0-HB) were determined from _ data. Using the vane method, the static yield stress (0s), the dynamic yield stress (0d) and the shear modulus (G) were determined. Effect of pasting temperature and ageing time were also studied by the vane method. Addition of sugars produced an increase in all rheological parameters except 0d, suggesting that sugars increased the strength of the internal bonds or cohesiveness of the GSDs; in general, fructose was slightly more effective than sucrose. Equivalent parameters: G0 and G, and 0-HB and 0s showed good agreement. Decreasing the heating temperature increased G. GSDs with fructose showed a clear increase in 0s and G with ageing time.
Key Words: starch sugar rheology vane yield stress
Food Science and Technology International, Vol. 10, No. 1,
51-57 (2004) |
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