Phenylethyl yeast

The main volatiles in wines are the higher aliphatic alcohols, ethyl esters, and acetates formed from yeasts during fermentation. Acetates are very important flavors characterized by fruity notes, C4-Ci0 fatty acid ethyl esters manly confer fruity scents to the wine. Other wine aroma compounds are C6 alcohols, such as 1-hexanol and cis- and trans-3-hexen-l-ol, 2-phenylethanol, and 2-phenylethyl acetate. Contents of these compounds in wine are linked to the winemaking processes used fermentation temperature, yeast strain type, nitrogen level in must available for yeasts during fermentation, clarification of wine (Rapp and Versini, 1991). Much literature on the wine aroma compounds was reported in reviews by Schreier (1979) and Rapp (1988). 

As part of their metabolism, all yeasts are known to produce a wide range of esters such as ethyl acetate, isoamyl acetate, isobutyl acetate, ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, and 2-phenylethyl acetate (Nykanen and Nykanen, 1977 Soles et al., 1982 Edwards et al., 1990 Webster et al., 1993 Rojas et al., 2001 2003 Plata et al., 2003 Lee et al., 2004). Esters are synthesized through reaction of alcohols (commonly, ethanol) and carboxylic acids by different acyltransferases or ester synthases (Mason and Dufour, 2000). Factors that affect ester synthesis include grape maturity, sugar content, fermentation temperature, and juice clarity (Houtman et al., 1980a 1980b Edwards etal., 1990). 

Inquiries into the possible production of behavioral chemicals of D. frontalis by microorganisms associated with it have been carried further. As mentioned above, two fungi and two yeasts are associated with the mycangium of the female (440, 441). The production of various volatile substances, other than ethanol, by actively fermenting yeasts is well established (445). Brand et al. (446) grew three yeasts obtained from D. frontalis, namely H. holstii, P. pinus, and P. bovis, on Sabouraud s dextrose broth, and identified isoamyl alcohol, 2-phenylethanol, isoamyl acetate and 2-phenylethyl acetate as the main volatile substances (other... 

Metabolic inactivation, whether taking place in the e,r. or at other sites, is often accidentally inhibited by other drugs. Thus many patients have died as a result of the simultaneous administration of an inhibitor of monamine oxidase (an enzyme present in mitochondria) and an amine drug which is not toxic on its own. Thus the inhibitor phenelzine (9.36) (phenylethyl-hydrazine) has caused deaths after usually safe doses of amphetamine, pethidine, nortriptyline, or amitriptyline, or after the patient has consumed amine-rich food such as cheese, red wine, meat-extract, yeast-extract, or broad beans. These are examples of unfortunate synergism, but many favourable examples are known, examples of which will now be given. 

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