Mono and diglycerides of fatty acids
Mono and diglycerides of fatty acids are nutrients well known to our body, which receives them through nutrition both directly and indirectly (from triglycerides hydrolysed during digestive processes ). Let us 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 glycerol molecule . If we remove one or two fatty acids from this structure respectively, 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 characteristic 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 individual 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 formed naturally in the rancidity process , so much so that the maximum content of free fatty acids in oils is regulated by law (also because they give the product a decidedly unpleasant flavour ). In the industrial field, these additives are produced synthetically from glycerol and individual fatty acids, or obtained from by-products of the oil industry.
Since it is not possible to trace a priori the type of fatty acids linked to glycerol, therefore knowing the percentages of saturated , unsaturated and hydrogenated fatty acids , we cannot formulate a precise health opinion on these additives. These are obviously safe substances, given their normal presence in foods and the continuous origin of triglycerides from digestive processes. The health impact remains doubtful, however, given that in theory for functional needs a producer of a food without hydrogenated fats could then use mixtures of mono and diglycerides rich in trans fatty acids . Even if mainly vegetable oils are used , the use of animal fats cannot also be excluded .
Other widely used additives are the esters of mono- and diglycerides of fatty acids, in which the free hydroxyl groups of glycerol are esterased with acetic acid, lactic acid, citric acid , tartaric acid or combinations thereof. These additives (E 472 a, b, c, d, e, f) are used – due to their emulsifying and stabilizing capacity – especially in baked products such as bread, breadsticks and rusks .
