PGPR, the full name of polyglycerol polyricinoleate, is an ingredient commonly used as a water-in-oil type (W/O) emulsifier in chocolate and chocolate-type confectionary to reduce the viscosity in production. It is a type of polyglycerol esters (PGE) with the European food additive number E476.
PGPR is a mixture of esterified products manufactured by the esterification of polyglycerol with condensed castor oil fatty acids. The brief 3 step manufacturing processes as follows:
1. Polyglycerols preparation: Glycerol is heated to above 200 ℃ in the presence of an alkali catalyst to produce polyglycerol.
2. Condensation of the castor oil fatty acids: Castor oil fatty acids (synthesized by hydrolysing castor oil in water) are heated to above 200 ℃ to create interesterified ricinoleic fatty acid chains of varying lengths.
3. Esterification: Then polyglycerol mixed with interesterified ricinoleic fatty acids to produce PGPR with different chain lengths. (1)
Fatty acids In Castor Oil
Castor oil is a vegetable oil that can be pressed from castor beans. It is mainly composed of ricinoleic acid (85–95%). Other components are oleic acid (2–6%), linoleic acid (1–5%), stearic acid (0.5–1%) and palmitic acid (0.5–1%). (2)
Clear, highly viscous liquid.
It is strong lipophilic W/O emulsifier and can form stable emulsions even when the water content is very high.
Insoluble in water and in ethanol; soluble in ether.
PGPR consists of polyglycerol as the hydrophilic group and interesterified ricinoleic fatty acids as the hydrophobic group in its structure.
The common applications of PGPR are as an emulsifier in chocolates. It also can be used in confectionery fillings to reduce fat and improve the flow properties, and in low-fat spreads to stabilize the emulsion and improve mouthfeel and spreadability.
What is this ingredient in chocolate?
It is common to see it in the ingredients list of the chocolate candy which you might find in the supermarket. Let’s see its functions in chocolate.
1. Viscosity reduction agent
PGPR has good thermal stability. The most important advantage in chocolate manufacturing is its ability in preventing crystals occur by reducing the viscosity of the chocolate slurry, thereby improving its fluidity, accelerating and optimizing the chocolate moulding process.
2. Eliminating bubble formation and empty holes
PGPR also help release small bubbles generated during the moulding process, thereby avoiding bubbles and holes in the chocolate product.
3. Synergistic with lecithin
It has a good synergistic effect when used together with lecithin (an emulsifier, E322).
4. Reduction of cocoa butter
It can significantly reduce the shear stress and the amount of cocoa butter needed (to reduce the cost for chocolate manufacturers) in chocolate formulations, along with the reduction of the thickness of the chocolate coating, and improve the ease of processing.
What other food may contain it?
The following products may with it (3):
- Spreadable fats
- Cocoa products
- Cocoa-based confectionery
- Emulsified sauces
Yes, PGPR has been approved as a safe emulsifier by U.S. Food and Drug Administration (FDA), European Food Safety Authority (EFSA), as well as Joint FAO/WHO Expert Committee on Food Additives (JECFA).
The FDA had no question on Palsgaard’s conclusion that PGPR is Generally Recognized as Safe (GRAS) when used as an emulsifier in chocolate-type products based on vegetable fats other than cocoa butter in the maximum levels 0.3%. (4)
Polyglycerol polyricinoleate (E476) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “Additives other than colours and sweeteners” (5).
Safety re-evaluation in 2017
In 2017, after the study on genotoxicity, carcinogenicity, reproductive and developmental toxicity, the EFSA concluded that polyglycerol polyricinoleate as a food additive at the permitted uses and levels would not be of safety concern and derived the following conclusions (6):
PGPR is metabolized to free polyglycerols, polyricinoleic acid and free ricinoleic acid in the gut after oral dosing in rats.
- Ricinoleic acid: It is safe as an edible fats and oils and it was not of toxicological concern nor possible allergenicity.
- Polyglycerol: safe to contact with all types of food when used in plasticiser at a maximum level of 6.5% w/w in polymer blends of aliphatic baromatic polyesters.
ADI: EFSA may change the acceptable daily intake (ADI) of 7.5 mg/kg bw per day to 25 mg/kg bw per day in 2020 after a 2-year combined chronic toxicity/carcinogenicity study and derived a no observed adverse effect level (NOAEL) of 2,500 mg/kg bw per day. (7)
UK Food Standards Agency
Categorized in “Emulsifiers, stabilisers, thickeners and gelling agents” (8)
Food Standards Australia New Zealand
It is an approved ingredient in Australia and New Zealand with the code number 476. (9)
JECFA (Joint FAO/WHO Expert Committee on Food Additives)
Function Class: food additives, emulsifier. (10)
Acceptable daily intake: ADI “7.5 mg/kg bw” set in 1973. (11)
It is common that sometimes consumers have health concerns whether PGPR is bad for our health and what are the side effects. We understand that consumers prefer natural food and have concerns about synthetic food additive in the foods we eat. PGPR is generally considered safe but some population may be allergic to it.
Does PGPR cause cancer?
No, a study published in Food Chem Toxicol in 1998 demonstrated that no carcinogenic effect of PGPR was observed. In this study, diets containing 5% of this ingredient were given to 120 rats for 2 years and 50 mice for 80 weeks. (12)
Another report published in Food Chem Toxicol in 1998 concluded that PGPR in tin-greasing emulsions or in chocolate couverture does not pose a human health hazard from a lot of researches conducted from late 1950s and early 1960s, including acute toxicity tests, animal carcinogenicity tests, human clinical evaluation and so on. (13)
Is PGPR Natural?
No, it is not natural as mentioned above, it is made from the reaction of glycerol and fatty acids.
Is PGPR Halal?
Yes, it is halal and comply with the diet policy of Muslims and we can find some China manufacturers certificated with MUI halal.
Is PGPR Kosher?
Yes, it is kosher pareve. E476 has met all the “kashruth” requirements and has been certified as kosher.
Is PGPR Gluten free?
Yes, it is gluten free and comply with the FDA’s definition of gluten free, that it does not contain wheat, rye, barley, or crossbreeds of these grains. And it is generally considered safe for people with celiac disease.
Is PGPR Vegan?
Yes, it is vegan as it derived from vegetable sources of glycerol and castor oil, the manufacturing process without the use of animal matter or products derived from animal origin. However, glycerol can also be sourced from animal fats & oils, so vegetarians should avoid this derivation.
Now I think you may have a good knowledge of the emulsifier – PGPR (E476), from the production process, uses and function in chocolate, approved safety and possible side effects. Also you may be clear with some common FAQs such as is it gluten free and vegan.
What kinds of food packaging have you found this ingredient in? Let me know in the comments.