Chemical and FunctIonal PropertIes of GelatIn
Gelatin’s first use started as animal glue in ancient times by boiling animal bones and hides, and evolved through history to be used in many applications in different industries. Its many useful characteristics allow it to be such a wide-spread and popular ingredient.
Gelatin forms colloidal solutions with water, hence it’s called hydrocolloid. Hydrocolloids, such as gelatin, carrageenan, pectin, are used for their multifunctionality. Gelatin compared to other hydrocolloids is more multifunctional and irreplaceable for many applications.
Gelatin has two groups of functional properties:
1) GELLING PROPERTIES:
Gel formation
Gelatin forms colloidal solutions or sols when mixed with water. Upon cooling sols turn into gels, upon heating they revert to sols. This property of gel formation is called thermorevesibility.
Theoretically, gelatin has unlimited thermoreversibility when forming gels, which sets it apart from other hydrocolloids which form irreversible gels or form gels with limited reversibility. This property also gives gelatin that “melt in mouth” characteristic that gelatin desserts are popular for.
Gelling strength is measured in units called Bloom values. We offer wide range of Bloom values from 150 to 280. The higher the number, the firmer the resulting gel, the lighter the colour.
Texturizing
Gelatin provides silky texture and smooth mouth feel to food products, such as soups, meats, sauces.
Thickening
Gelatin increases the viscosity of solutions, helping to achieve the desired consistency of the final product, making it softer or firmer.
Water binding
Gelatin has affinity toward water molecules and easily binds large number of water molecules. This ability helps gelatin to preserve integrity of products, such as dairy products, and prevent them from losing water and contracting/shrinking (syneresis).
2) SURFACE EFFECTS PROPERTIES:
Emulsion formation and stabilization
Emulsions are fine dispersions of one liquid in another, which are usually unmixable (immiscible), such as oil and water.
Gelatin facilitates the formation of emulsions by stabilizing the fine dispersed droplets, and preventing the mixture from separating.
Protective colloid function
Gelatin can act as an effective protective colloid. It can stabilize and prevent the aggregation/flocculation of crystals and particles in heterogenous suspensions and dispersions. For example, in ice creams gelatin enhances the formation of fine crystals, thus preventing coarse crystallization of lactose in the mixture.
Foam formation and stabilization
When small bubbles are dispersed in a liquid or solid medium, it’s called foaming. Just as with emulsions, gelatin facilitates the foam formation by protecting the foam by forming thin film around the bubbles. Gelatin also stabilizes the foam by increasing the viscosity of the medium. For example, in marshmallows gelatin enhances the foam formation and stabilizes the foam by hardening the marshmallow.
Film formation
Gelatin makes it possible to convert liquids into a thin, pliable sheets allowing its shape to manipulated for necessary applications. This property is useful in manufacturing of nutraceutical and pharmaceutical gelatin capsules.
Adhesive property
Gelatin has stickiness that allows it to act as a binding agent. For example, in cereal bars gelatin can be used to make the ingredients stick together.