Polyglycerol polyricinoleate, or PGPR, is an additive used in chocolate, margarine, ice cream, cooking oils and other food products as an emulsifier. Hershey's and other chocolate manufacturers use PGPR to help keep the water and fat in their products from separating and also to improve consistency.
PGPR is derived from castor bean oil, and it was first used in England in the 1950s. It is now one of the most common emulsifiers used in chocolate products, along with soy lecithin. Hershey's claims that it primarily uses PGPR to improve the viscosity of chocolate, allowing chocolate to flow better during manufacturing so it can be pumped into various molds and shapes. The chemical is also used to produce reduced-fat products.
Using PGPR as a replacement for cocoa butter allows chocolate manufacturers to significantly reduce manufacturing costs. The use of PGPR in chocolate products prevents Hershey's and other chocolate manufacturers from claiming that their products are pure chocolate due to regulations from the U.S. Food and Drug Administration (FDA). According to the FDA, PGPR is safe for use in food production, but the organization recommends that humans consume no more than 7 1/2 milligrams per kilogram of body weight of PGPR per day.