Yeast and Its Effect on the Flavour of Alcoholic Beverages*

Abstract

Sensory examination of an aroma model consisting of alcohols, fatty acids, esters and aldehydes, in concentrations estimated in whisky, has proved thatin addition to vicinal diketones-esters predominate as components influencing the aroma, but also some fatty acids exercise a most marked influence. Further more, some people possess a good ability to smell certain compounds whereas others cannot smell them as well, but detect other compounds more easily.Within the group of more than 100 identified aroma components, mainly the same substances appear in the volatile aroma fraction of beer, wine and distilled beverages. In view of this, it seems evident that the raw materials utilized for the production of the beverages contribute to no more than a limited extent towards the aroma composition. The aroma components which are most notice able are produced by the yeast during fermentation, and the nature of the final aroma first and foremost depends upon the kind of yeast used, and upon the fermentation conditions. Although the yeast for the most part produces the same aroma components also in different beverages, considerable variation may occur in the quantities of aroma components even in beverages of the same type.The structure and function of the plasma membrane selectively regulate the uptake of different compounds from the medium into the yeast cell, and the release of the metabolites from the cell into the medium. In this sense, the lipid composition of the plasma membrane and its lipolytic enzymes may possess a decisive importance. The activity of the lipolytic enzymes present in the plasma membrane must be controlled by some regulatory mechanism. If this is the case, the permeability of the plasma membrane can be modified, e.g., by activation of the phospholipases, with consequent degradation of membrane phospholipids.Consequently, it is likely that one of the functions of the lipolytic enzymes present in the plasma membrane is that of participation in the transport processes by changing the permeability properties of the plasma membrane.

Wine flavour

“…After this point, the winemaker can selectively influence the flavour of wines in several ways. During the primary or alcoholic fermentation, yeast (Saccharomyces cerevisiae) converts sugar to ethanol, carbon dioxide and several by-products, which include ethyl esters, fusel alcohols and phenethyl alcohol [2,3]. Although the production of terpenes by yeast during fermentation has been reported [4], only low levels of one mono terpene , farnesol, were produced by S. cerevisiae.…”

Produção de álcoois superiores por linhagens de Saccharomyces durante a fermentação alcoólica

“…No caso das bebidas alcoólicas, os álcoois superiores desempenham papel importante no aroma (RANKINE, 1967;SUOMALAINEN, 1971).…”

Composição química de aguardentes de cana-de-açúcar obtidas por fermentação com diferentes cepas de levedura Saccharomyces cerevisiae

“…As condições de fermentação influenciam preponderantemente o sabor das bebidas (SUOMALAINEN, 1971;SUOMALAINEN;LEHTONEN, 1979 …”

“…Os álcoois superiores aparecem de forma natural durante o processo fermentativo de produção de bebidas, sendo compostos importantíssimos na definição do sabor e do aroma de bebidas destiladas (RANKINE, 1967;SUOMALAINEN, 1971).…”