Wines fermentation

Maturation regimes vary from as tittle change as possible in many white and pink wines (stainless steel tanks, cool storage, minimum time) to considerable modification in red table and a few white table wines. Fermentation and storage in fairly new 200-L barrels for about 6 mo is not uncommon for Chardoimay and white Burgundy wines. Many robust red table wines such as those from Cabernet Sauvignon grapes are often stored similarly, after fermentation and initial clarification, for up to about 3 yr in such barrels. 

Mutation. For industrial appHcations, mutations are induced by x-rays, uv irradiation or chemicals (iiitrosoguanidine, EMS, MMS, etc). Mutant selections based on amino acid or nucleotide base analogue resistance or treatment with Nystatin or 2-deoxyglucose to select auxotrophs or temperature-sensitive mutations are easily carried out. Examples of useful mutants are strains of Candida membranefaciens, which produce L-threonine Hansenu/a anomala, which produces tryptophan or strains of Candida lipolytica that produce citric acid. An auxotrophic mutant of S. cerevisiae that requires leucine for growth has been produced for use in wine fermentations (see also Wine). This yeast produces only minimal quantities of isoamyl alcohol, a fusel oil fraction derived from leucine by the Ehrlich reaction (10,11). A mutant strain of bakers yeast with cold-sensitive metaboHsm shows increased stabiUty and has been marketed in Japan for use in doughs stored in the refrigerator (12). 

The presence of solutes other than ethanol might be expected to reduce the mole fractions of ethanol and water and influence the nonideality of the ethanol-water system. However, both Williams (1983), who modelled a batch wine fermentation, and Rottenbacher (1985), in ethanol sorption experiments with yeast pellets in a fluidized bed, established that the ethanol-water-yeast system behaves as if the water and ethanol content of the pellets were a simple ethanol-water solution supported by a solid matrix which influences neither mole fractions nor activity coefficients. 

The trihasic salt is a water softener emulsifier and a nutrient for yeast production and wine fermentation. 

Lee, D.E., Swinny, E.E., and Jones, G.P., NMR identification of ethyl-linked anthocyanin-flavanol pigments formed in model wine ferments. Tetrahedron Lett. 45, 1671, 2004. 

Saccharomyces cerevisiae Actinobacillus succinogenes during wine fermentation Anaerobiospirulum succiniciproducens... 

Pilone, G. J., Kunkee, R. E., Sensory Characterization of Wines Fermented... 

The separation of alcohol from different raw materials like cider [13], wine fermentation broth [14], alcohol-water mixtures [15-18] and wine [19-22] is an interesting alternative to distillation processes especially if heat sensitive substances are present. Separex company separated the aroma substances out of whisky and cognac, which gives a very interesting product for food industry. 

Quality control and analysis in the agro-food industry by the low resolution NMR was reviewed by D. N. Rutledge [83], in which NMR method is described as faster, more precise, simpler and cheaper technique than those traditionally used. For on-line monitoring of wine fermentation, EtOH and sugar alcohol beverage and fermenting musts were determined to a precision of 0.005-0.1% for EtOH and 4 8g/L for sugar by low resolution NMR [84]. 

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