Formation of Esters from Acids by Brewer's Yeast: Formation from Unsaturated Acids

Abstract

ESTERS are supposed to be of importance as flavour determinants in many products. A considerable number of esters have been detected in fruits^1–8 and in fermented beverages^9–11. Jennings⁴ has shown that the desirable pear aroma is largely due to volatile esters. Esters are also used in essences (primarily the esters with 6–8 carbon atoms in acid + alcohol)^1,7 and are generally accepted to be important contributors to the flavour and aroma of beer and wine. The threshold concentration for flavour perception is very low for some esters: it is 0.01 p.p.m. for ethyl isobutyrate, for example, as has been reported by Harrison¹². Sihto and Arkima¹³ have reported that isopentyl acetate is deleterious to the flavour of berr at rather low concentrations.