PGPR (Polyglycerol Polyricinoleate)
What it does
Reduces viscosity in chocolate.
How it's made
Made from castor oil and glycerol.
PGPR (polyglycerol polyricinoleate) is a specialist emulsifier used mainly in chocolate, where a tiny amount dramatically reduces the thickness of the melted chocolate, letting it flow and mould better and reducing how much cocoa butter is needed. It is also used in some low-fat spreads.
It is made from two food-derived building blocks: polyglycerol, produced by joining several glycerol molecules together, and polyricinoleic acid, made from ricinoleic acid, which comes from castor bean oil. These two are combined by esterification to form the large PGPR molecule, which has a water-loving head and oil-loving tails.
The finished PGPR is purified and standardised into a viscous, yellowish liquid. It is extremely effective in very small quantities, which is why it appears near the end of chocolate ingredient lists; its castor-oil-derived component is thoroughly processed, and the additive is used strictly at the low levels permitted.
Possible reactions
Generally safe at the low levels used.