Poster ID:1143741580

Analysis of gum arabic and gum tragacanth using GPC-MALLS

click image to enlarge Analysis of gum arabic and gum tragacanth using GPC-MALLS

Author:Neil Pickles

Co-authors:S. Al-Assaf and J. H. H. Williams

Gum arabic, a gum exudate from Acacia senegal and Acacia seyal, is an important hydrocolloid used in the food industry as an emulsifier, stabiliser and thickener. Gum arabic and gum tragacanth were analysed using GPC-MALLS to give information on molecular weight, molecular species distribution, radius of gyration and polydispersity. Gum arabic contains three principal fractions, arabinogalactan protein (AGP), arabinogalactan (AG) and glycoprotein (GP). It is AGP that is the active component and is responsible for its emulsifying action. GPC-MALLS was able to identify this AGP fraction and to quantify the amount present. The difference between Acacia senegal and Acacia seyal can be determined by the molecular weight data and by comparing the responses of the three detectors. Tragacanth was characterised by GPC-MALLS and then compared to Acacia senegal. Tragacanth was found to have a higher molecular weight and different elution profile. Gum arabic and tragacanth were both subjected to enzyme digestion (protease) to digest any AGP present and then analysed by GPC-MALLS. Gum arabic showed the response that has previously been reported, a reduction in the high molecular weight peak (AGP region) with a corresponding decrease in molecular weight. Tragacanth however did not show any reduction in high molecular weight peak or decrease in molecular weight. This result suggests that tragacanth does not contain AGP and overall tragacanth is very different to gum arabic.

Poster presented at:
3rd National Meeting on Environmental Mass Spectrometry - 2006


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