Water-retaining agents are hygroscopic substances regulating the activity of water in alimentary products and thus preserving them from drying and associated undesirable changes of their structure and texture (most often, hardening).

The water-retaining agents are added to the products that lose their quality with the water loss. Due to their hygroscopicity, the water-retaining agent binds the water contained in the freshly-prepared product, thus preventing or considerably decreasing its evaporation. As a result the consistency of the original product (e.g., the sponge-cake) is preserved, and its freshness is extended. In the high-concentration syrups, the addition of such sugars as the glucose or invert sugar increased solubility of the saccharose, which helps to slow down its crystallization process; this allows to preserve the consistency of sugar confectionery (usually fondant paste candies) up to the expiry date of their shelf life.

The water-retaining agents permitted for use in alimentary products in the Russian Federation are the following:

Е322 lecithines, Е325 sodium lactate, Е326 potassium lactate, Е327 calcium lactate, Е339-341 sodium, potassium, calcium phosphates, Е400 alginic acid, Е401-404 sodium potassium, ammonium, calcium alginates, Е406 agar, Е420 sorbitol and sorbitol syrup, Е422 glycerin, Е440 pectins, Е450 pyrophosphates, Е452 polyphosphates, Е459 betacyclodextrin, Е542 bone phosphate, Е965 maltitol and maltitol syrup, Е1200 А and N polydextroses, Е1518 triacetin, Е1520 propylene glycol.