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Gelatinization of wheat starch as modified by xanthan gum, guar gum, and cellulose gum
- Christianson, D.D., Hodge, J.E., Osborne, D., Detroy, R.W.
- Cereal chemistry 1981 v.58 no.6 pp. 513-517
- shear strength, viscosity, guar gum, wheat starch, pasting properties, chemical treatment, gelatinization, xanthan gum, carboxymethylcellulose
- Amylograph curves and Corn Industry Viscometer curves show that guar, xanthan, and carboxy methylcellulose gum hasten the onset of inital paste viscosity and substantially increase final peak viscosity of wheat starch. The early onset of inital viscosity is attributed to detection of the first stage of swelling and is dependent on media viscosity only. Further development of paste consistency can be attributed to interactions of solubilized starch, gums, and swollen starch granules. Media isolated from starch-guar and starch-xanthan dispersions display synergistic viscosity, which remains stable at room temp. This viscosity stability suggests that strong associations of soluble starch (amylose) with gums are developed during pasting. Rheological behaviour of media isolated from starch-xanthan paste shows pseudoplasticity, whereas media from starch-guar pastes show some resistance to shear at low shear rates. Degree of amylose hydrolysis is reduced with β-amylase (E.C. 18.104.22.168) if wheat starch solubles isolated from starch-water pastes are reheated with either guar or xanthan gum before enzyme digestion.