E445 or Glycerol ester of wood rosin, is a food additive used in beverages and chewing gum.

For its preparation it is used rosin wood of Pinus palustris, subsequently worked with esterification process. Basically, it is obtained by combining glycerol with rosin (pine tree resin), which is a complex mixture of different substances.

The name describes the structure of the molecule:

• Glycerol also known as glycerine, is a trihydric alcohol with the formula C₃H₈O₃. It's a viscous, colorless liquid that's sweet-tasting.
• Ester of wood rosin refers to a derivative of wood rosin that has reacted with glycerol to form an ester.

Description of the raw materials used in its production:

• Glycerol - Glycerol, also known as glycerin, is the main raw material for the production of glycerol ester of wood rosin. It can be obtained from vegetable or animal sources through the hydrolysis of oils or fats.
• Wood Rosin - Wood rosin is a substance derived from the processing of resin from coniferous trees. It can be derived from various tree species, such as pine or fir.

Industrial chemical synthesis step-by-step:

• Extraction of Wood Rosin - Wood rosin is extracted from the tree through tapping or other extraction techniques.
• Purification of Wood Rosin - Raw wood rosin undergoes a purification process to remove impurities and other unwanted components. This may involve filtration or refining processes.
• Esterification Reaction - Purified wood rosin is reacted with glycerol in the presence of a catalyst, such as an acid, to form glycerol ester of wood rosin.
• Product Purification - The reaction product is purified to remove any impurities or unwanted by-products. This can be done through filtration or distillation processes.
• Characterization - The purified glycerol ester of wood rosin is characterized using various analytical techniques to confirm its identity, purity, and desired properties.

What it is for and where

Food

In the food sector it is labeled with the number E445 in the european list of food additives  with a thickening function. It is commonly found in drinks, particularly in citrus-flavoured soft drinks, where it serves to distribute the flavour evenly throughout the drink.

The Committee considered that the data from previously reviewed studies and the new studies were adequate to establish an ADI. Therefore, on the basis of the 13-week toxicity study in rats with food-grade material, in which the effect level was 2500 mg / kg bw per day, the Committee allocated an ADI of 0-25 mg / kg bw, pplying to safety factor of 100. The Committee did not round the ADI to one significant figure, because such a rounding would have resulted in a decrease in the value of the ADI of 20%.

The Food and Drugs Administration has approved this additive with the warning of an ADI (Acceptable daily intake) (2).

Applications

Food Additive - Functions as a stabilizer in non-alcoholic beverages, especially carbonated drinks. It helps to stabilize the orange oil in citrus-based drinks, maintaining an even suspension.

Chewing Gums - Used as a component in some chewing gums to impart a desirable texture.

Paint Industry - Can be used as a binder in some paint formulations.

Adhesives - Finds application in certain adhesives due to its ability to provide stickiness.

The most relevant studies on this chemical compound have been selected with a summary of their contents:

Glycerol ester of wood rosin studies

Synonyms:

• Ester gum

References____________________________________

(1) Dr G.J.A. Speijers  GLYCEROL ESTER OF WOOD ROSIN (food and beverage grade) Section on Public Health of the Advisory Centre of Toxicology,National Institute of Public Health and Environmental Protection(RIVM), Bilthoven, Netherlands

(2) https://www.fda.gov/ucm/groups/fdagov-public/@fdagov-foods-gen/documents/document/ucm260969.pdf