suspending agent

:  a substance (such as carrageenan, xanthan gum, or cellulose ether) that is added to fluids to promote particle suspension or dispersion and reduce sedimentation All these drinks can contain preservatives, and drinks other than juices can contain additives to colour, flavour and sweeten. They may also have … a suspending agent to prevent what fruit there is from falling sadly to the bottom of the bottle. — Derek Cooper, The Beverage Report, 1970