|Khouryieh, John (hanna)|
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2007
Publication Date: 4/1/2007
Citation: Khouryieh, J., Herald, T.J., Aramouni, F., Bean, S., Alavi, S. 2007. Influence of Deacetylation on the Rheological Properties of Xanthan-Guar Interactions in Dilute Aqueous Solutions. Journal of Food Science. 72:C173-C181. Interpretive Summary: Gluten-free foods, while safe for celiac patients, are often low in quality due to the absence of gluten. To overcome this problem, glucose based gums such as xanthan are often used as gluten replacements. In order to produce higher quality gluten-free food products, such as those made from sorghum, the functionality of gums needs to be better understood. This research was conducted to better understand the effect of modifying xanthan gum on its interaction with other gums. Mixtures of guar and xanthan gum were found to have higher viscosities than either gum used alone. Deactylating xanthan was found to increase the interaction between xanthan and guar, improving the properties of the mixtures even more. Understanding gums and their interactions will help to produce improved gluten-free food products.
Technical Abstract: An oscillating capillary rheometer was used to investigate the effects of xanthan deacetylation on the viscoelastic properties and intrinsic viscosity of xanthan and guar mixtures in dilute aqueous solutions. Deacetylated xanthan exhibited a stronger synergistic interaction with guar than native xanthan did. No gels were observed for all xanthan-guar mixtures. Native xanthan-guar mixtures exhibited a liquid-like behavior, whereas deacetylated xanthan-guar mixtures exhibited a gel-like behavior. The relative viscosity and elasticity of deacetylated xanthan-guar mixtures were much stronger than those for native xanthan-guar mixtures. The intrinsic viscosities of deacetylated xanthan-guar mixtures were higher than those calculated from the weight averages of the two individually, whereas the intrinsic viscosities of native xanthan-guar mixtures were lower than those calculated from weight averages of the two individually, demonstrating that intermolecular binding occurred between xanthan and guar gum in dilute aqueous solutions.