The mono and diglycerides of fatty acids are nutrients well known to our body, which receives them through food both directly and indirectly (from hydrolyzed triglycerides during digestive processes). Remember that the most abundant lipids in nature are triglycerides. , hydrophobic molecules (not soluble in water) formed by the union of three fatty acids with a molecule of glycerol. If we remove one or two fatty acids respectively from this structure, we obtain the mono and diglycerides of fatty acids.
Unlike fatty acids, glycerol is a water-soluble molecule. It follows that by subtracting one or two fatty acids from the structure of a triglyceride, the water solubility of the lipid increases considerably. This feature is useful in the industrial field, where mono and diglycerides of fatty acids (E471) are mainly used as emulsifiers, therefore for their ability to keep aqueous phases "united" (water - thanks to the OH of glycerol) with oily phases (oil - thanks to fatty acids). In this regard, it has been known for many years that specific mixtures of mono and diglycerides of fatty acids have a higher emulsifying power than single compounds. Generally, esters of saturated and unsaturated fatty acids with carbon chains exceeding 16 carbon atoms are used.
Mono and diglycerides of fatty acids are naturally formed in the rancidity process, so much so that in oils the maximum content of free fatty acids is regulated by law (also because they give the product a decidedly unpleasant taste). In the industrial field, these additives are produced synthetically starting from glycerol and single fatty acids, or obtained from by-products of the oil industry.
Since it is not possible to go back a priori to the type of fatty acids linked to glycerol, and therefore to know the percentages of saturated, unsaturated and hydrogenated fatty acids, we cannot formulate a precise health judgment on these additives. These are obviously safe substances, given their normal presence in food and the continuous origin of the digestive processes of triglycerides. However, the health impact remains doubtful, given that in theory for functional needs a producer of a food free of hydrogenated fats could then use mixtures of mono and diglycerides rich in trans fatty acids. Even if mainly vegetable oils are used, it cannot also be excluding the use of animal fats.
Other widely used additives are the esters of mono and diglycerides of fatty acids, in which the free hydroxyl groups of glycerol are esterified with acetic acid, lactic acid, citric acid, tartaric acid or their combinations. These additives (E 472 a, b, c, d, e, f) are used - for their emulsifying and stabilizing capacity - above all in baking products such as bread, breadsticks and rusks.
