Saccharomyces cerevisiae in the Production of Fermented Beverages

Abstract

Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively) strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre-hydrolysis) in the case of beers and whiskies, sucrose-rich plants (molasses or sugar juice from sugarcane) in the case of rums, or from fruits (which do not require pre-hydrolysis) in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites) as the cells strive to make energy and regenerate the coenzyme NAD + under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of such beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations.

Bread Dough and Baker's Yeast: An Uplifting Synergy

“…For example, S. cerevisiae cannot fix atmospheric nitrogen and requires the supply of organic nitrogen (amino acids) or inorganic nitrogen (ammonium salts). Next to nitrogen sources, minerals, and especially key metal ions, are important determinants of yeast performance (Walker and Stewart 2016 impact on yeasts during brewing and distilling fermentations. For example, increasing free Mg 2+ in fermentation media increased alcohol production, while maintaining high Mg 2+ :Ca 2+ ratios in fermentation feedstocks is important for maximal fermentation performance (Walker and others 2006).…”

Microbial and Chemical Diversity of Traditional Non-Cereal Based Alcoholic Beverages of Sub-Saharan Africa

“…Common consortia harbor yeasts, acetic acid, and lactic acid bacteria [34]. The diversity in carbon metabolism pathways among the different microbes in the consortia, allows mixed culture fermentation towards the production of different primary and secondary metabolites that influence the overall aromatic complexity of the alcoholic beverage [65][66][67]. Such mixed culture fermentation has become common in the wine and beer industries in an effort to improve the distinctive flavors of the alcoholic beverages.…”

“…Grapes for example, harbor a number of fermenting yeasts on their skins such as Kloeckera spp., Hanseniaspora spp., Candida spp., Pichia spp., Kluyveromyce spp., Metschnikowia spp., and Cryptococcus spp. [67,70,71] with Hanseniaspora uvarum, Pichia terricola, and Metschnikowia pulcherrima being the three most representative species isolated to date [69]. The most well-known and best fermenting yeast, S. cerevisiae, however, is found in very low frequencies on some fruits such as the grape skins, and in vineyards soils [72].…”

“…Esters are formed through esterification of activated fatty acids and alcohols [109]. The amount of esters produced during fermentation depends on the abundance of the corresponding alcohols and acyl CoAs [67]. Esters can either be found in the starting material albeit at lower concentrations [110] or formed intracellular by microorganisms.…”

Microencapsulation of Baker’s Yeast in Gellan Gum Beads Used in Repeated Cycles of Glucose Fermentation

“…Yeasts, especially Saccharomyces species, are generally chosen for the production of ethanol due to an important fermentation capacity, a good tolerance to ethanol and other inhibitors, and their capability of rapid growth under anaerobic conditions which are characteristic of fermentation processes [10,11].…”