INS 551 is amorphous silicon dioxide, or silica, numbered E551 in Europe. Codex lists it as an anticaking agent, antifoaming agent and carrier. Chemically it is the same compound as quartz, but food-grade silica is non-crystalline and made synthetically, usually by precipitating it from a sodium silicate solution or by burning silicon tetrachloride to give a very light “fumed” silica.
Its fine, porous particles soak up moisture and oil and sit between powder grains so they cannot stick together. That keeps seasoning powders, cheese powders and instant mixes free-flowing even in humid weather, so the flavour coats each piece evenly. It has no taste of its own.
It appears in many seasoned snacks on SeekSnack: in the seasoning of several Lay’s flavours, such as Lay’s Stax Spicy Lobster, in Taokaenoi’s crispy seaweed, and, together with talc, in the Royal Chitralada Milk Tablet.
