Abstract

The effect of addition of xanthan gum (0.05, 0.1, 0.15, 0.25% weight/volume) on the formation and rheology of whey protein isolate (WPI)-xanthan gum gels has been investigated at neutral pH. The elastic modulus (G') values of the gelling test were compared. Low concentration of xanthan added (<0.05%,w/v) has a synergistic effect on the gel strength depend on phase separation, so that whey proteins concentrated in their phase and finally mixed gels with xanthan would be stronger than WPI gels. At higher xanthan concentration (> 0.05%, w/v), antagonist effect was observed by reducing the connection between clusters of whey protein by xanthan, so aggregation disruption and a related decrease in (G'). The phase separation microstructure of WPI-stabilized emulsion containing xanthan gum added has been investigated by rheology and confocal laser scanning microscopy. Xanthan was stained with Fluorescein 5(6)-isothiocyanate (FITC). Low xanthan concentration addition lead to depletion flocculation and increasing the xanthan concentration cause to increase the viscoelasticity of aqueous phase, so retarded macroscopic phase separation over period investigated. Structural changes in emulsion were observed in viscoelastic properties of separated phase in the rheometer. The CLSM image shows different phase which have different viscoelastic properties; xanthan-rich region transforms into the spherical shape which has the lowest interfacial energy and gradually two separated ultimately.

Erratum

This version contains substantial errors and was replaced by a corrected version on February 12th, 2008. You may find the corrected version as a Related File at:
http://www.bepress.com/ijfe/vol3/iss4/art9

Submitted: May 23, 2006 · Accepted: February 27, 2007 · Published: August 24, 2007

Recommended Citation

Nayebzadeh, Kooshan; Chen, Jianshe; and Mousavi, SM Mohammad (2007) "Interactions of WPI and Xanthan in Microstructure and Rheological Properties of Gels and Emulsions," International Journal of Food Engineering: Vol. 3 : Iss. 4, Article 9.
DOI: 10.2202/1556-3758.1104
Available at: http://www.bepress.com/ijfe/vol3/iss4/art9

Related Files

IJFE_MS_1104_Corrected.pdf (1443 kB)
Corrected Version. Issued February 12th, 2008.