Acetic acid tragacanth

Flavor emulsions are similarly stabilized by the viscosity produced upon addition of a vegetable gum, such as tragacanth, Irish moss extract, arabic, a cellulose gum, or one of the alginates, to the aqueous phase. Here the oil phase, in the form of the flavor, is in small proportion to the water. In the absence of the acetic acid, contained in the vinegar of the French dressing. 

At pH 7, tragacanth has been reported to considerably reduce the efficacy of the antimicrobial preservatives benzalkonium chloride, chlorobutanol, and methylparaben, and to a lesser extent that of phenol and phenylmercuric acetate. However, at pH < 5 tragacanth was reported to have no adverse effects on the preservative efficacy of benzoic acid, chlorobutanol, or methylparaben. ... 

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