Maltol is a naturally occurring organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 that is used primarily as a flavor enhancer. It is found in the bark of larch

Larch

Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...

 tree, in pine

Pine

Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

 needles, and in roasted malt

Malt

Malt is germinated cereal grains that have been dried in a process known as "malting". The grains are made to germinate by soaking in water, and are then halted from germinating further by drying with hot air...

 (from which it gets its name). It is a white crystalline powder that is soluble in hot water, chloroform, and other polar solvents. Because it has the odor of cotton candy and caramel, maltol is used to impart a sweet aroma to fragrances. Maltol's sweetness adds to the odor of freshly baked bread, and is used as a flavor enhancer (E number

E number

E numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...

 E636) in breads and cakes.

Maltol, like related 3-hydroxy-4-pyrone

Pyrylium salt

A pyrylium salt is a salt containing a pyrylium cation or a derivative of it. The pyrylium cation is a conjugated 6-membered carbon ring system with one carbon atom replaced by a positively charged oxygen atom. It is, like benzene, an aromatic compound...

s such as kojic acid

Kojic acid

Kojic acid is a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine...

, binds to hard

HSAB theory

The HSAB concept is an acronym for 'hard and soft acids and bases. Also known as the Pearson acid base concept, HSAB is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways....

 metal centers such as Fe³⁺, Ga³⁺, Al³⁺, and VO²⁺. Related to this property, maltol has been reported to greatly increase aluminum uptake in the body and to increase the oral bioavailability of gallium

Gallium

Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...

and iron.