Etil-maltol

What it is

The preferred IUPAC name of ethyl maltol is 2-ethyl-3-hydroxy-4H-pyran-4-one. It is a common flavourant in some confectioneries. It is a white crystalline powder with the formula C₇H₈O₃ and a molar mass of about 140.14 g/mol.

Natural and synthetic

Maltol is also produced during the roasting of malt and in the baking of bread. Maltol has the odor of caramel and is used to impart a pleasant aroma to foods and fragrances. Ethyl maltol itself is purely synthetic.

Chemistry

The conjugate base derived from ethyl maltol has a high affinity for iron, forming a red coordination complex. In such compounds, the heterocycle is a bidentate ligand. Ethyl maltol is sparingly soluble in water and soluble in propylene glycol. It is also soluble in ethanol.

Specification

The JECFA specification describes ethyl maltol as a white crystalline powder with a characteristic odour and requires an assay of not less than 98%. Its melting range is 89 to 93 °C. Water content may not exceed 0.5%, sulfated ash may not exceed 0.2%, and lead may not exceed 1 mg/kg. It carries the INS number 637 and the functional classes flavouring agent and flavour enhancer.

Uses and regulation

Ethyl maltol is used as an additive in a wide range of beverages, perfumes, ice cream, cakes, confections, e-liquids, cigarettes and oral medications. In the European Union it has the food additive code E 637. Because of its lack of toxicity, it is approved to be dosed quantum satis, which means as much as necessary. It has been evaluated by JECFA and EFSA. Typical concentrations in food range between 1 and 100 ppm, depending on the application.

Food and drink tests

Ten parts per million of ethyl maltol in grape juice greatly amplifies the natural sweet grape aroma, and pineapple juice flavor is pleasingly enhanced at 4 ppm. Sherry wine has an improved flavor at 5 ppm, an orange-type liqueur is sweetened at 10 ppm, and the fruit flavor of a low calorie orange drink is enhanced at 1 ppm. In chocolate bars it increases the richness of the chocolate flavor, creates a blended taste and lifts the aroma. Creme candies containing 20 ppm had significantly better flavors than candies without it. In a strawberry-flavored gelatin dessert, ethyl maltol at about one fifth to one half of the maltol level gives a more flavorful product than maltol does.

Comparison with maltol

In a patent test of dilute solutions, the sample containing 500 ppm of maltol had about the same odor intensity as the sample containing 100 ppm of ethyl maltol.

In e-liquids

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