What Is Glycerol Ester of Wood Rosin / Ester Gum (E445)? Applications, Dosage, Alternatives & Specifications

Glycerol Esters of Wood Rosin, commonly known as Ester Gum, Rosin Glyceride, Glyceryl Rosinate, also called Glycerol Ester of Rosin, is a light-colored thermoplastic resin produced by the esterification of wood rosin (a natural resin harvested from pine trees) with food-grade glycerol. It is a multifunctional food additive and industrial tackifying resin, with wide application value in the global food industry, adhesives, coatings, and daily chemical industry. Its CAS number is 8050–31–5, INS number is 445(iii), EU E number is E445, and CNS number is 10.013. It has no precise chemical structural formula, with the main components being triabietin (glyceryl triabietate) and smaller amounts of diabietin (glyceryl diabietate) and monoabietin. Glycerol Esters of Wood Rosin is a synthetic compound formed by the esterification of wood rosin (a natural resin from pine trees) with plant-derived glycerol. It is a pale, thermoplastic rosin ester with properties that make it suitable for various applications. Because wood rosin is sourced from renewable natural resources, Glycerol Esters of Wood Rosin combines natural attributes with a lower environmental footprint compared to traditional synthetic additives such as brominated vegetable oil [0†L14-L16]. Compared with rosin, it has a significantly lower acid value, reduced brittleness and tack, improved weather resistance, and is no longer corrosive to metals. Depending on the raw material source, Glycerol Esters of Wood Rosin can be classified into Gum Rosin Glycerol Ester, Wood Rosin Glycerol Ester (GEWR), and Tall Oil Rosin Glycerol Ester. Among these, GEWR is the most widely used variety in the food industry. Industrial-grade ester gum is widely used in adhesives, coatings, inks, rubber, and electronic encapsulating materials. Different types of ester gum can be further modified by hydrogenation, polymerization, or partial dimerization to adjust properties such as softening point, color, oxidation resistance, and odor. In the food industry, Glycerol Esters of Wood Rosin is mainly used as a weighting agent and emulsifying stabilizer. In citrus-flavored beverages, ester gum acts as a weighting agent to increase the density of the oil phase, making it closer to the density of water, thereby preventing oil separation and “ringing” and ensuring uniform distribution of ingredients. It has a natural emulsifying stabilizing effect [8†L15-L20]. In chewing gum and bubble gum, ester gum is used as a gum base component, providing excellent elasticity, chewiness, and improved mouthfeel. Ester gum is a lipophilic emulsifier with beverage-stabilizing properties and can be used to adjust the density of citrus oils. In the industrial field, Glycerol Esters of Wood Rosin is widely used as a tackifying resin in hot-melt adhesives, pressure-sensitive adhesives, EVA hot-melt adhesives, and sealants. It forms transparent systems with high-performance polymers. In coatings, inks, and the rubber industry, ester gum enhances gloss, adhesion, and weatherability, and is also an important component of paints, bookbinding adhesives, and pipe adhesives.

Glycerol Esters of Wood Rosin is recognized as a natural, multifunctional food additive weighting agent and industrial tackifying resin, holding an important position in modern food, beverage, adhesive, and coating industries. Its most outstanding core advantages lie in its renewable natural origin, its excellent emulsifying and suspension stability in beverage systems, and its exceptional tackifying and flexibility-modifying properties for adhesives and coatings.

Renewable Natural Origin: Glycerol Esters of Wood Rosin is made from pine tree rosin and plant-derived glycerol, making it a bio-based, renewable material. Compared to traditional synthetic additives like brominated vegetable oil, ester gum offers natural attributes and a lower carbon footprint, meeting the growing global demand for clean-label, sustainable, and environmentally friendly materials in food and industrial markets. Ester gum produced by companies like Eastman is manufactured under rabbinical supervision for Kosher certification and Halal certification, expanding its application in diverse global markets.