High-sugar yeast

High Sugar Yeasts. These are products specially produced to work under the high osmotic pressures in products like Danish pastries. These yeasts are available in the form of IADY products. There are also some Japanese strains of compressed yeast that can stand high osmotic pressures. 

Alcoholic Fermentation. Certain types of starchy biomass such as com and high sugar crops are readily converted to ethanol under anaerobic fermentation conditions ia the presence of specific yeasts Saccharomyces cerevisia and other organisms (Fig. 6). However, alcohoHc fermentation of other types of biomass, such as wood and municipal wastes that contain high concentrations of cellulose, can be performed ia high yield only after the ceUulosics are converted to sugar concentrates by acid- or enzyme-catalyzed hydrolysis ... 

Dried fruits and concentrated fruit juice are very susceptible to spoilage by yeasts, because of their relatively high sugar and moisture contents. Some species of Zygosac-charomyces, Torulaspora, and Lachancea have been associated with spoilage of these products (Dijksterhuis and Samson 2006). 

For the new wine to contain the desired 15-16 vol % alcohol, it is necessary to add some sugar to the juice or the partially fermented wine except in cases of unusually high sugar content in the grapes. In any event, it is necessary to have an accurate estimate of the sugar concentration in the juice before more sugar is added and before fermentation starts. It is better not to add the calculated amount of sucrose to the juice immediately but to make two or three smaller additions after the fermentation is actively under way. This technique is known as syruped fermentation and can yield wines of as much as 17 vol % alcohol under favorable conditions of yeast nutrients and temperature control. 

Erasmus, D. J., van der Merwe, G. K., and van Vuuren, H. J. (2003). Genome-wide expression analyses Metabolic adaptation of Saccharomyces cerevisiae to high sugar stress. FEMS Yeast Res. 3, 375-399. 

Due to the high sugar contents involved in the mead production, fermentation tends to be slow and requires a yeast strain as well as pH, temperature, and growth conditions that are optimal. 

During mead fermentation, several problems are generally encountered. For example, the anticipated alcohol content may not be achieved within the time desired. There may also be a lack of uniformity in the final product, due to differences in water content of the honey used. In some situations, such as worts with high sugar contents, successive addition of honey is needed to avoid premature termination of fermentation. This likelihood of stuck fermentation is increased as most mead is made empirically, without adjustments. This can lead to subsequent yeast refermentation and secondary fermentations by lactic and acetic acid bacteria. These can undesirably increase acidity and the production of volatile esters (Casellas, 2005). The presence of these compounds alters... 

The high sugar content of the juice dramatically reduces the growth, fermentation rate, and survival of yeasts (Dittrich, 1977 Lafon-Lafourcade, 1983) and also affects secondary metabolism. Acetic acid... 

In the meanwhile, yeasts adapt themselves to the cold conditions and begin alcoholic fermentation. Fermentation is slow but regular, usually carried out by Saccharomyces cereuisiae and Saccharomyces bayanus. The fermentation has to be kept under constant surveillance as the low temperatures, combined with the high sugar content, may lead to premature and unwanted fermentation cessation, even when selected cultures of yeasts are added. 

High fructose corn syrup or sugar Yeast... 

Lafon-Lafourcade, S., Larue, F., and Ribereau-Gayon, P. 1979. Evidence for the existence of survival factors as an explanation for some peculiarities of yeast growth, especially in grape must of high sugar concentration. Appl. Environ. Microbiol. 38, 1069-1073. 

It is worth mentioning in particular the spoilage of foods and beverages characterized by high sugar contents, low pH, and low water activities (flw) by yeasts as posing a major economic problem (Hazan, Levine,... 

Only a few yeasts and bacteria are able to spoil wine, because of the high sugar content, low pH, high alcohol concentrations, and anaerobic fermentation conditions (Du Toit, Pretorius, and Lonvaud-Funel, 2005). 

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