Glucono-delta-lactone (GDL), also known as gluconolactone, is a

food additive Food additives are substances added to food to preserve Taste, flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), sal ...

with the E-number E575 used as a sequestrant, an

acidifier Acidifiers are inorganic chemicals that, put into a human (or other mammalian Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce mi ...

, or a curing, pickling, or leavening agent. It is a lactone 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 ...

. 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. 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 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 Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

energy as one gram of

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or do ...

. 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 In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the ...

. 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 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