My Ester: Glucono delta-lactone

Glucono delta-lactone (GDL) is a cyclic Ester, lactone, is a naturally occurring food additive. The FDA approved uses of the ester include use as a curing and pickling agent, leavening agent, pH control agent, and sequestrant which is a food additive whose role is to improve the quality and stability of the food products. Pure dry GDL is a white odorless crystalline powder. Although GDL is neutral, the hydrolyzed form is gluconic acid which is acidic.Gluconic acid occurs naturally in fruit, honey, and wine. This acid adds a tangy taste to food and is roughly a third of the sourness of citric acid. It is metabolized to glucose. One gram of GDL yield roughly the same amount of metabolic energy as one gram of sugar. 


With the addition of water the ester is partially hydrolyzed to gluconic acid, forming a chemical equilibrium between the lactone form and gluconic acid. The rate of hydrolysis will increase with increasing temperature and high pH.  Thus it is soluble in water. Also the melting point of GDL is 153 degrees Celsius. 


I could not find the exact carboxylic acid/ alcohol pair GDL is derived from, I believe it can be synthesized from glucose since it has the same amount of carbons as glucose and hydroxy groups. It simply has to be hydrolyzed.




Sources: 
1. http://en.wikipedia.org/wiki/Glucono_delta-lactone
2. http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5067074
3. http://en.wikipedia.org/wiki/Glucose