Glucono delta-lactone explained

Glucono-delta-lactone (GDL), also known as gluconolactone, is an organic compound with the formula . A colorless solid, it is an oxidized derivative of glucose.

It is typically produced by the aerobic oxidation of glucose in the presence of the enzyme glucose oxidase. The conversion cogenerates hydrogen peroxide, which is often the key product of the enzyme:

Gluconolactone spontaneously hydrolyzes to gluconic acid:^[1]

Applications

Gluconolactone is a food additive with the E-number E575^[2] used as a sequestrant, an acidifier,^[3] or a curing, pickling, or leavening agent. It is a lactone of D-gluconic acid. Pure GDL is a white odorless crystalline powder.

GDL has been marketed for use in feta cheese.^[4] GDL is pH-neutral, but hydrolyses in water to gluconic acid which is acidic, adding a tangy taste to foods, though it has roughly a third of the sourness of citric acid. It is metabolized to 6-phospho-D-gluconate; one gram of GDL yields roughly the same amount of metabolic energy as one gram of sugar.

Upon addition to water, GDL is partially hydrolysed to gluconic acid, with the balance between the lactone form and the acid form established as a chemical equilibrium. The rate of hydrolysis of GDL is increased by heat and high pH.^[5]

The yeast Maudiozyma bulderi can be used to ferment gluconolactone to ethanol and carbon dioxide. The pH value greatly affects culture growth. Gluconolactone at 1 or 2% in a mineral media solution causes the pH to drop below 3.^[6]

It is also a complete inhibitor of the enzyme amygdalin beta-glucosidase at concentrations of 1 mM.^[7]

See also

• Glucuronolactone

Notes and References

1. 10.1007/s00253-008-1407-4 . Glucose oxidase: Natural Occurrence, Function, Properties and Industrial Applications . 2008 . Wong . Chun Ming . Wong . Kwun Hei . Chen . Xiao Dong . Applied Microbiology and Biotechnology . 78 . 6 . 927–938 . 18330562 . 2246466 .
2. Web site: Current EU approved additives and their E Numbers. https://web.archive.org/web/20220422201759/https://www.food.gov.uk/business-guidance/approved-additives-and-e-numbers. 22 April 2022. Food Standards Agency.
3. Martin . F. . Cayot . N. . Marin . A. . Journaux . L. . Cayot . P. . Gervais . P. . Cachon . R. . 3 . 10.3168/jds.2009-2491 . Effect of oxidoreduction potential and of gas bubbling on rheological properties and microstructure of acid skim milk gels acidified with glucono-δ-lactone . Journal of Dairy Science . 92 . 12 . 5898–5906 . 2009 . 19923593 . free . 2019-08-16 . 2020-03-11 . https://web.archive.org/web/20200311074809/https://hal.archives-ouvertes.fr/hal-01191294/file/publi_2559_%7B40AD2DFA-2D5E-4727-A4C1-201FC5A3210E%7D.pdf . live .
4. Web site: Inside the food industry: the surprising truth about what you eat . Blythman . Joanna . 21 February 2015 . The Guardian . en . 28 October 2016 . bot: unknown . https://web.archive.org/web/20160813231549/https://www.theguardian.com/lifeandstyle/2015/feb/21/a-feast-of-engineering-whats-really-in-your-food . 13 August 2016.
5. Pocker . Y. . Green . Edmond . Hydrolysis of D-Glucono-δ-lactone. I. General Acid–Base Catalysis, Solvent Deuterium Isotope Effects, and Transition State Characterization . J. Am. Chem. Soc. . 95 . 1 . 113–19 . 1973 . 4682891 . 10.1021/ja00782a019.
6. Van Dijken . J. P. . Van Tuijl . A. . Luttik . M. A. . Middelhoven . W. J. . Pronk . J. T.. Novel pathway for alcoholic fermentation of delta-gluconolactone in the yeast Saccharomyces bulderi . Journal of Bacteriology . 184 . 3 . 672–678 . 2002 . 11790736 . 139522 . 10.1128/JB.184.3.672-678.2002.
7. Petruccioli . M. . Brimer . L. . Cicalini . A. R. . Federici . F.. Production and Properties of the Linamarase and Amygdalase Activities of Penicillium aurantiogriseum P35 . Bioscience, Biotechnology, and Biochemistry . 63. 5 . 805–812 . 1999 . 10380623 . 10.1271/bbb.63.805. free .