Mono and diglycerides, also called mono- and diglycerides of fatty acids, saturated or unsaturated, are a mixture of monoglycerides (commonly with 40-90%) and diglycerides, and also includes minor amounts of triglycerides. It is the most used emulsifier in the food and with the European food additive number E471.
Mono and diglycerides is a group of emulsifiers and the following are the common types (with the only difference in fatty acids):
- Glycerol monostearate
- Glycerol monopalmitate
- Glycerol monooleate
- Glycerol monolaurate
- Glycerol monoricinoleate
Although these products only have one fatty acid that starts with “mono” before a fatty acid in the names, actually they’re the mixture of mono and diglycerides and may also contain triesters.
Esters Of Mono and Diglycerides
Mono and diglycerides can be esterified with other food grade acidulants (acetic acid, citric acid, lactic acid or tartaric acid) to produce another category of emulsifiers – E472 as follows and ethoxylated mono-and diglycerides:
- Acetic acid esters of mono- and diglycerides of fatty acids (E472a, ACETEM)
- Lactic acid esters of mono- and diglycerides of fatty acids (E472b, LACTEM)
- Citric acid esters of mono- and diglycerides of fatty acids (E472c, CITREM)
- tartaric acid esters of mono- and diglycerides of fatty acids (E472d, TATEM)
- Mono- and diacetyl tartaric acid esters of mono- and diglycerides of fatty acids (E472e, DATEM)
- Mixed acetic and tartaric acid esters of mono- and diglycerides of fatty acids (E472f, MATEM)
As mentioned above, it mainly consists following three compositions:
It may also contain small percentages of free fatty acids and glycerol.
The difference between monoglycerides and diglycerides is that monoglycerides are obtained by glycerol (E422) esterification with one fatty acid (E570) while diglycerides is derived from glycerol reaction with two fatty acids.
In the below example of monoglycerides, glycerol is esterified with a saturated fatty acid, palmitic acid.
Following is an example of diglycerides obtained by esterified glycerol with a saturated fatty acid – palmitic acid (blue color), and an unsaturated fatty acid – elaidic acid (green color).
Monoglycerides and Diglycerides Percentages
The common content of monoglycerides in commercial food grades of mono- and diglycerides are 40%, 60% or 90%.
Following is a table from the EFSA regarding the composition (% by weight) of monoglycerides, diglycerides, triglycerides and others in different food grades of mono and diglycerides of fatty acids in the market.
The main raw materials involved in the production of mono and diglycerides are fatty acids and glycerol, both are naturally present in edible fats/oils of animals (e.g. cow, pig) and vegetable (various plant seeds).
Generally, mono and diglycerides can be made from two manufacturing processes, transesterification process or direct esterification process.
Transesterification means a reaction between an ester and an alcohol.
Mono- and diglycerides can be obtained by the glycerolysis reaction between fats /oils with glycerol, for example between methyl ester and glycerol in the presence of an alkaline catalyst (e.g. NaOH, KOH).
Diglycerides and triglycerides can also be produced in the reaction. (1)
The following is the equilibrium reactions:
Further distillation and other processes can be done to separate/refine monoglycerides and diglycerides, such as to produce distilled monoglycerides.
Direct esterification process
It can also be synthesized by the esterification between glycerol and fatty acids.
Below is the reaction equation:
The common vegetable sources of fatty acids and glycerol are as follows:
- Palm oil
- Coconut oil
- Soybean oil
- Rapeseed oil
- Sunflower oil
- Cottonseed oil
The common fatty acids including:
- Stearic acid
- Palmitic acid
- Lauric acid
- Linoleic acid
- Myristic acid
- Oleic acid
Glycerol is also called glycerine or glycerin, it has three hydroxyl groups, which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides, and triglycerides.
It is a multi-functional ingredient that can be used as a sweetener, humectant, and thickener in the food and pharmaceutical industry.
It is available both in liquid and solid form:
- Liquid: a pale yellow to pale brown oily liquid
- Solid: white ﬂake, powder or beads
Soluble in fat, not soluble in water.
Hydrophilic – Lipophilic Balance (HLB)
The lower the HLB value of an emulsifier indicates that it is more soluble in oil and can form W/O (water in oil) emulsions, or otherwise it is more soluble in water and forms O/W (oil in water) emulsions.
In the molecule of mono and diglycerides, glycerol is hydrophilic while the fatty acid long chain is lipophilic.
It forms W/O (water in oil) emulsion and generally, the HLB value ranges from 3 to 6.
Mono- and diglycerides is a multi-functional ingredient that primarily used as emulsifiers in the following food and for the purpose of:
- Bread: function as a dough softener, also improves loaf volume and the texture, and therefore prolongs bread freshness and shelf life.
- Cake mix: improve cake volume and texture, also improve crumb structure and tenderness.
- Margarine: stabilize the emulsion.
- Cream & Creamers: enhance the stability of the emulsion system such as in coffee mate.
- Ice cream: improve the creamy mouthfeel, stabilize the air in ice, create a stable structure and reduce freezing time.
- Spreads & Butter: improve the emulsion stabilization and spreadability, reduce stickiness, improve flavour.
- Cheese: to obtain a smooth texture, such as in peanut butter.
- Desserts: benefit aeration and foam stability.
Yes, it has been approved as a safe ingredient by the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), as well as the Joint FAO/WHO Expert Committee on Food Additives (JECFA).
Mono and diglycerides are a multi-functional ingredient which are generally recognized as safe (GRAS) that can be used as an emulsifier, stabilizer, thickener, texturizer, dough strengthener, surface-active agent (and so on) in food with no limitation other than current good manufacturing practice. (2)
It is also generally recognized as safe when used as an emulsifying agent in feed. (3)
Mono- and Diglycerides of fatty acids (E471) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “Additives other than colours and sweeteners” (4).
Its application is listed in Group I with the usage “not limited”and separately. The following food may contain it (5):
- Unflavoured pasteurised cream
- Fats and oils (free from water)
- Bread and rolls
- Processed potato products
- processed eggs and egg products
- Jam, jellies and marmalades and sweetened chestnut purée
- Cocoa and Chocolate products
- Quick-cook rice
- Table-top sweeteners in tablets
- Infant formulae
Safety re-evaluation in 2017
After the studies of genotoxicity, carcinogenicity, reproductive and developmental toxicity and other researches, EFSA concluded there were no safety concerns when mono- and di-glycerides of fatty acids used as a food additive and no need for a numerical acceptable daily intake (ADI). (6)
UK Food Standards Agency
Categorized in “Others” (7)
Food Standards Australia New Zealand
It is an approved ingredient in Australia and New Zealand with the code number 471. (8)
Function Class: food additives, emulsifier. (9)
Acceptable daily intake: ADI “not limited” set in 1973. (10)
Generally, there are no observed adverse effects of monoglycerides and diglycerides when used as an emulsifier. However, sometimes consumers are worried that it may do bad to our health due to the trans fatty acids that may in it.
Do Mono and Diglycerides really contain Trans fatty acids?
EFSA pointed out during the safety re-evaluation of mono and diglycerides of fatty acids in 2017, that it may increase the amounts of trans fatty acids in final products if it is manufactured by glycerolysis (transesterification process) of hydrogenated fats and/or oils.
Furthermore, the European Commission is considering putting the item of “maximum limits for trans fatty acids” in its speciﬁcations for mono- and diglycerides.
How does Trans fatty acids occur?
It is also called trans-unsaturated fatty acids, which are produced during the partial hydrogenation process of naturally occurring vegetable oils as physical properties of parts of the unsaturated fatty acids (exist in the vegetable oils ) may be altered, changed from cis-unsaturated fatty acids to trans-unsaturated fatty acids in such process.
Trans fatty acids health risk
Human studies show that intake of trans fatty acids may increase the risk of developing coronary heart disease. (11)
Is it Natural?
No. Mono and diglycerides is a synthetic emulsifier which is made from chemical synthesis, the direct esterification between glycerin and fatty acids or the transesterification of glycerin with fats/oils (triglycerides).
Is it Halal, Kosher and Vegan?
Yes, mono and diglycerides are halal, kosher and vegan if fatty acids and glycerol come from vegetable oils. As the starting raw materials derived in these ways, complies with:
- The diet policy of Muslims, so it is Halal.
- Jewish religious dietary law, so it is Kosher.
- Vegetarians diet as the production without the use of animal matter or products derived from animal origin, therefore it is vegan.
Is it Gluten free?
Yes, it is gluten free as it does not contain wheat, rye, barley, or crossbreeds of these grains. And can be used for people with celiac disease.
Is it a Fat?
Monoglycerides and diglycerides are not fat, but triglycerides are. A fat is formed when three hydroxyl groups on glycerol combine with three fatty acids.
Now you may have a knowledge of the emulsifier – Mono and diglycerides (E471), from the following aspects:
- Several types of mono and diglycerides based on different assay of monoglycerides and diglycerides, and various kinds of fatty acids linked to glycerol.
- Two production processes: from transesterification process and direct esterification process.
- Uses in food
- Possible side effects: due to the existence of trans fatty acids
- FAQs: is it natural, halal, vegan, gluten free, fat.
If you have any questions or remarks about this additive, feel free to let me know in the comments.