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 ). Recall 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 glycerol molecule . 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 the 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 fatty acids are used and unsaturated with carbon chains that exceed 16 carbon atoms.
Mono and diglycerides of fatty acids are formed naturally 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, thus knowing 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 . Although mainly vegetable oils are usedthe use of animal fats cannot also be excluded .
Other additives widely used 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 combinations thereof. 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, bread sticks and rusks .