Fermentation congeners

Gin is produced entirely from neutral spirits too (i.e., without the fermentation congeners), but has an aromatic flavor element derived from a final distillation over juniper berries or from added coriander seeds (a member of the carrot family). 

Congeners. Congeners are the flavor constituents in beverage spirits that are responsible for its flavor and aroma and that result from the fermentation, distillation, and maturation processes. 

Wash. Wash is the hquid obtained by fermenting wort with yeast. It contains the beverage spitits and congeners developed during fermentation. 

The flavor and aroma of distilled spidts are derived primarily from minor constituents called congeners that are produced and augmented in the fermentation and maturation processes. The congener profiles for various distilled spidts are shown in Table 2. 

Yeast (qv) metabolize maltose and glucose sugars via the Embden-Meyerhof pathway to pymvate, and via acetaldehyde to ethanol. AH distiUers yeast strains can be expected to produce 6% (v/v) ethanol from a mash containing 11% (w/v) starch. Ethanol concentration up to 18% can be tolerated by some yeasts. Secondary products (congeners) arise during fermentation and are retained in the distiUation of whiskey. These include aldehydes, esters, and higher alcohols (fusel oHs). NaturaHy occurring lactic acid bacteria may simultaneously ferment within the mash and contribute to the whiskey flavor profile. 

Cachaqa and aguardente de cana are the most consumed distilled spirits in Brazil exclusively made from cane-sugar juice. Sugar and caramel maybe added for colour adjustment. The total content of congeners is between 200 and 650 mg 0.1 L p.e. Like other spirits, the flavour of cacha a is mainly characterised by the presence of fermentation by-products such as higher alcohols, esters, carboxylic acids, and carbonyl compounds [41-43]. 

Thus, the concentrations of fatty acids and esters found in brandy distillates are greatly affected by the nature of the wine at the time of distillation, particularly the time interval between fermentation and distillation since most of the yeast cells settle out fairly quickly after fermentation has ceased. Obviously the degree of resuspension of the settled lees into the wine when distilled affects the amount of fatty acids and esters recovered in the distillates. The method and techniques of distillation are also very important since this class of congeners, having relatively high boiling points and weak solubility in water, exhibit wide ranges of volatility as affected by the alcohol content of the liquid volatilized. 

The aldehydes and fusel oils recoverd from distillation are also referred to as congeners, or flavor components. Most of the aldehyde content is acetaldehyde, although other aldehydes are also present. The fusel oils (from the German fuselol meaning bad spirits ) are thought to arise via yeast fermentation of amino acids present in the original mash. They include amyl, and isoamyl alcohols (about 50%), n-butanol (about 20%), and a residue of fatty acids and several other higher alcohols [47] (Eq. 16.17). 

The S. lividam sn s SorAB, SorABRCDFE, and SorABRCDFE+BL were fermented in the presence of thiostrepton to induce the expression of the soraphen biosynthetic genes, but no production of soraphen A, or any other soraphen congener was found by LC-MS analyses (Table I). As there is no evidence that S. lividam has the capacity to biosynthesize the soraphen starter unit benzoyl-CoA as part of its normal metabolism (3S), we tried to ferment these strains while feeding benzoate SorABRCDFE+BL, but not the other two strains, produced soraphen A as shown by antifungal bioassay and LC-MS analysis (Figure 2C and D, Table I). In conclusion, both an external source of benzoate and the introduction of a suitable benzoyl-CoA ligase [the BadA entyme of R palustris (37)] were necessaiy for soraphen A production in S. lividam. 

The rational bases for the expectation that examination of microbial fermentations can provide important new antibacterial antibiotic discoveries have already been explored. For some of the respondents there is also an element of faith involved. What is expected is not rebirth of the era of prolific discoveries but the isolation and recognition in the next decade of a few significantly improved congeners of antibiotics already in use, a few antibiotics belonging to new structural classes which will have important therapeutic advantages, and a few new prototype structures worthy of chemical modification. 

Whisky. Whiskey, A liquid produced by distillation of the fermented mash of malted cereal grains, which has been stored in wood containers for noi less than 4 years. Straight whisky contains 47 -55% abs alcohol by voL 0.05 -0.16% acid calculated as acetic acid, and 0.038-0.15% esters as ethyl acetate. Whisky marked 100 proof contains 50% ethanol (v/v). It also contains small quantities of other natural constituents (congeners), which vary according to the grain used, method of fermentation, etc., and which are largely responsible for the characteristic aroma and flavor. 

Okaramines have attracted considerable attention due to their molecular complexity and intriguing biogenesis. We thoroughly searched the fermented material of P. simplicissimum ATCC 90288 for new okaramine congeners, with the result that nine members of the okaramine family were isolated. 

Most of the substances found in the culture broth to be separated are polar components. Besides, the very low concentration of many other components (apart from ethanol and water), called congeners, lead to difficulties to correlate and predict the concentration of the distilled product in the continuous extractive fermentation. Some of these substances (acetic acid, flufural, and methanol) are considered as a source of valuable co products [3], so that further downstream separation is justifiable. 

Alcoholic beverages contain a wide variety of materials other than ethanol and water. The particular combination and level of these compounds derives from the materials used and the fermentation process employed and confers on each beverage its distinctive colour, aroma and taste. These impurities, which are referred to as congeners, are generally more toxic than alcohol and are often associated with the deleterious after effects of alcohol consumption. The total congener content among alcohol beverages varies from as little as 3g per 100 litres in vodka to about 285 g per 100 litres in bourbon and comprises principally acetaldehyde, ethyl... 

Accordingly, it was shown that mycotrienins I (95) and II (96) possessed the same structures as those of the ansamycin antibiotics designated as ansatrienins A and B isolated from the fermentation broth of Streptomyces collinus [161, 162], except for the configuration of the alanine moiety. Thus, the alanine moiety of the ansatrienins was reported to be L, and was later revised to be d (the same configuration as those of mycotrienins). Ansatrienins A2 (100) and A3 (101) were isolated as minor congeners of ansatrienins A (95) and B (96) from the same fermentation broth [163]. 

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