Isoamyl propionate

Description

Isoamyl propionate has an apricot-pineapple odor. The taste is somewhat harsh when freshly distilled but subsequently yields apleasant apricot-plum bittersweet flavor. May be prepared by esterification of propionic acid with the isomeric amyl alcohols obtained from fusel oil and other sources.

Chemical properties

Clear colorless liquid

Chemical properties

Isoamyl propionate has a pineapple–apricot odor. The taste is somewhat harsh when freshly distilled, but subsequently yields a pleasant apricot–plum, bittersweet flavor

Occurrence

Reported found in Bulgarian peppermint, cocoa, apple, melon, tomato, Camembert and Gruyere cheese, hop oil, beer, cognac, rum, cider, red and white wine, apple wine and brandy, cherimoya and custard apple

The Uses of Isoamyl propionate

Perfumes, lacquers, flavors.

Preparation

By esterification of propionic acid with the isomeric amyl alcohols obtained from fusel oil and other sources.

Definition

ChEBI: A propanoate ester of isoamylol.

Aroma threshold values

Detection: 8.6 to 43 ppb; aroma characteristics at 2.0%: sweet, estry, fruity apple, banana with a fresh green, slightly tropical nuance

Taste threshold values

Taste characteristics at 30 ppm: sweet, banana, fruity, tutti-frutti, apple, melon, tropical and pineapple-like.

Hazard

Fire hazard.

Flammability and Explosibility

Flammable

Biochem/physiol Actions

Taste at 30 ppm

Metabolism

Esters such as propionates are hydrolysed to materials that are normally in the diet or are readily converted to such materials (Fassett, 1963a). The lower toxicities of the higher propionate esters (isoamyl < n-butyl < n-propyl < ethyl) and of the higher isoamyl esters (isovalerate < n-butyrate < propionate < acetate) were attributed to their slower rates of hydrolysis, which made less free alcohol available (Selisko, Ackermann & Kupke, 1962). The metabolism of propionic acid is known to proceed by conversion to succinic acid and oxidation through the citric acid cycle(Fassett, 1963b).