Glucono-delta-lactone (GDL), also known as gluconolactone, is a food additive with the

E-number E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly f ...

E575 used as a

sequestrant A sequestrant is a food additive which improves the quality and stability of foods. A sequestrant forms chelate complexes with polyvalent metal ions, especially copper, iron and nickel, which can prevent the oxidation of the fats in the food. Se ...

, an

acidifier Acidifiers are inorganic chemicals that, put into a human (or other mammalian) body, either produce or become acid. These chemicals increase the level of gastric acid in the stomach The stomach is a muscular, hollow organ in the gastroin ...

, or a curing,

pickling Pickling is the process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar. The pickling procedure typically affects the food's texture and flavor. The resulting food is cal ...

, or

leavening agent In cooking, a leavening agent () or raising agent, also called a leaven () or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action (gas bubbles) that lightens and softens the mixture. An altern ...

. It is a

lactone Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the co ...

of D-

gluconic acid Gluconic acid is an organic compound with molecular formula C6H12O7 and condensed structural formula HOCH2(CHOH)4COOH. It is one of the 16 stereoisomers of 2,3,4,5,6-pentahydroxyhexanoic acid. In aqueous solution at neutral pH, gluconic acid f ...

. Pure GDL is a white odorless

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

line powder. GDL has been marketed for use in

feta cheese Feta ( el, φέτα, ) is a Greek brined white cheese made from sheep's milk or from a mixture of sheep and goat's milk. It is soft, with small or no holes, a compact touch, few cuts, and no skin. Crumbly with a slightly grainy texture, it is ...

. 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 The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste recepto ...

citric acid Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in ...

. 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 Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

to gluconic acid, with the balance between the lactone form and the acid form established as a

chemical equilibrium In a chemical reaction, chemical equilibrium is the state in which both the Reagent, reactants and Product (chemistry), products are present in concentrations which have no further tendency to change with time, so that there is no observable chan ...

. The rate of hydrolysis of GDL is increased by heat and high pH. The yeast ''

Saccharomyces ''Saccharomyces'' is a genus of fungi that includes many species of yeasts. ''Saccharomyces'' is from Greek σάκχαρον (sugar) and μύκης (fungus) and means ''sugar fungus''. Many members of this genus are considered very important in f ...

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. It is also a complete inhibitor of the enzyme

amygdalin beta-glucosidase In enzymology, an amygdalin beta-glucosidase () is an enzyme that catalyzes the chemical reaction : (''R'')-amygdalin + H2O \rightleftharpoons (''R'')-prunasin + D-glucose Thus, the two substrates of this enzyme are (''R'')-amygdalin and H2O, ...

at concentrations of 1 mM.

References

{{reflist Food acidity regulators Curing agents Delta-lactones Pickling agents Leavening agents Sequestrants Garde manger Tetrahydropyrans E-number additives

See also

References