Glucono delta-lactone

What are the allowable sources of glucono delta-lactone and how is it used in organic processing?

By Johanna Mirenda

Glucono delta-lactone is derived from gluconic acid, with numerous uses as a food processing aid. Nonsynthetic forms of glucono delta-lactone are allowed for use in organic processing in accordance with its listing at §205.605(a) of the National List. Glucono delta-lactone is produced when gluconic acid  crystallizes in water. It is then isolated by filtering or centrifugation. Since glucono delta-lactone is generally sold in pure form, the review of ancillary substance is typically not an issue of concern.

Gluconic acid is naturally occurring in various foods and can be commercially manufactured in a number of ways. Production by oxidation of D-glucose with bromine water is specifically prohibited by the annotation for glucono delta-lactone on the National List. The most common commercial source of gluconic acid that is allowed for glucono delta-lactone production under organic regulations is that produced by microbial oxidation of glucose during fermentation. The fermentation process utilizes Aspergillus niger as the active microbe and a submerged culture medium. 

Glucono delta-lactone was originally petitioned for use as a coagulant in tofu production. It can be used in production of “silken” tofu (which has a yogurt-like consistency) by mixing with hot soymilk directly into retail containers. This process reduces the chance of microbial fermentation and extends the product’s shelf life.

Glucono delta-lactone has several other applications in food production because of its acidic and chelating properties. It is used as an acidifier in the production of dairy products that require a slow reduction in pH, such as cottage cheese, feta cheese and mozzarella. It is also used as an acidifier in salad dressings and ready-to-eat pasta and rice. Glucono delta-lactone is used as curing agent in processed meat products. It is also used as a leavening agent in bread and pastries, and causes a slower rate of carbon dioxide release compared to other leavening agents. All of these Generally Recognized as Safe (GRAS) applications of glucono delta-lactone are allowed in organic food processing.

This article was originally published in the Spring 2016 edition of the OMRI Materials Review newsletter.