Glycerol Rosin esters is formed by the reaction of carboxylic acid group of a rosin acid with glycerol. Glycerol rosin esters differ in property and application depending on the source of rosin acid. There are three sources from which rosin acids can be derived - gum, wood and tall oil rosin. These rosin acids are collected from stumps of longleaf pine trees. Glycerol ester of gum rosin is a hard, yellow to pale amber-coloured solid which is insoluble in water but soluble in acetone. They are used as an emulsifier and as density adjustment agent for flavouring oils in beverages. It is a complex mixture of tri- and di-glycerol esters of resin acids from gum rosin, with a residual fraction of mono-glycerol esters.
Glycerol ester of gum rosin is obtained by the esterification of refined gum rosin under nitrogen atmosphere with food-grade glycerol, and purified by counter-current steam distillation. The refined gum rosin used for manufacturing of glycerol ester of gum rosin is obtained by extracting oleoresin gum from living pine trees and refining it through washing, filtration and distillation. Wood rosin is obtained by the solvent extraction of aged pine stumps whereas tall oil rosin is a by-product of Kraft (paper) pulp processing.
Glycerol rosin ester is used in cosmetics industry as an emulsifier, stabilizer, and thickener.
Food and Beverage Industry
The main function of glycerol rosin ester in food and beverages is to keep oils suspended or mixed evenly in water. It acts as a thickening agent in ice creams and chewing gum. It is even used as an ingredient as it provides a pleasant and authentic fruit flavour in water-based beverages.
Paint and Coating Industry
Glycerol Rosin Esters is used in product lacquer furniture, varnish, hammer finish, metallic paint and ink. It is used as a pressure sensitive adhesive in paint and coating industry.