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Effect of gamma irradiation on rheological properties of polysaccharides exuded by A. fluccosus and A. gossypinus.

Abstract

In this study, Iranian gum tragacanth (GT) exudates from Astragalus fluccosus (AFG) and Astragalus gossypinus (AGG) were irradiated at 3, 7, 10 and 15 kGy. Fourier transform infrared spectroscopy (FTIR) data showed that irradiation did not induce changes in the chemical structure of either type of gum. Although particle size distribution and both steady shear and dynamic rheological properties were considerably affected by the irradiation process, the magnitude of the effect of irradiation on each of the rheological and size variables was different for the hydrocolloids. For instance, for AGG, increasing the irradiation dose from 3 to 10 kGy, the d(0.5) and D[3,2] values were reduced by one-sixth to one-eighth fold. Colour measurement revealed that the radiation process led to an increase in the yellow index and b* values for both types of GT in powder form, but it was more pronounced for AGG samples. Irradiation led to an approximate 13-fold increase in redness in AFG. Surface and shape changes of the gum crystals were studied by scanning electron microscope (SEM) and a smoother surface for irradiated samples was detected. The notable changes in functional properties of each variety of irradiated gum should be taken into consideration before using the radiation technology as a commercial tool for sterilisation.

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  • Publisher Full Text
  • Authors

    Alijani S, Balaghi S, Mohammadifar MA

    Source

    International journal of biological macromolecules 49:4 2011 Nov 1 pg 471-9

    MeSH

    Astragalus Plant
    Color
    Elastic Modulus
    Elasticity
    Gamma Rays
    Models, Chemical
    Particle Size
    Rheology
    Spectroscopy, Fourier Transform Infrared
    Tragacanth
    Viscosity

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    21664372