gélification

Gélification is the process by which a liquid becomes a gel, a semi-solid, viscoelastic material in which the liquid phase is immobilized by a three‑dimensional network. The transition occurs when polymer chains or colloidal particles form a spanning network that arrests flow and imparts solid-like behavior.

Gelation can be physical (reversible) or chemical (irreversible). Physical gelation involves non-covalent interactions such as hydrogen bonding, hydrophobic associations, or crystallite formation that can dissociate upon heating. Chemical gelation involves covalent crosslinking between chains through chemical reactions or enzymatic processes, yielding a permanent network. The resulting gel’s structure and properties depend on concentration, temperature, pH, and ionic strength.

In food science, gélification is exploited to create textures and stability. Common gelling agents include gelatin, agar, carrageenan, and pectin; for polysaccharide gels, sugar and acid conditions often influence gel strength. Starch gelatinization, by contrast, refers to the heating-induced swelling of starch granules and is mechanistically distinct from network gelation.

In materials science and medicine, gélification underpins hydrogels and polymer gels used in drug delivery, wound dressings, cosmetics, and soft robotics. Rheological measurements identify the gel point, typically where the storage modulus (G’) becomes comparable to or exceeds the loss modulus (G’’), signaling a transition from liquid-like to solid-like behavior.

Terminology varies by language: gélification is the French term for gel formation, while English typically uses gelation; the two are closely related and often used interchangeably in francophone scientific literature.