Nitrogen-containing compounds grapes

The concentration and composition of nitrogen-containing compounds in grape must plays a crucial role in the nutrition of microorganisms involved... 

The Scuppemong grape has a distinctive flavor characteristic. Kep-ner and Webb (47) analyzed the volatile essence of this grape and identified six alcohols, including 0-phenylethyl alcohol, five aldehydes, and five esters. No nitrogen or sulfur containing compounds were found which indicated the absence of methyl anthranilate. 

Grape and apple juices usually contain all of the trace nutrients required by Saccharomjces for fermentation of sugars to alcohol. Other fmit and diluted honey, as well as barley malt and rice extract, frequendy need additions of nitrogen, phosphoms, and potassium compounds, together with some autolyzed yeast to faciUtate the yeast growth necessary for fermentation. Stimulation oiy4.cetobacter frequendy requires the addition of autolyzed... 

Cheynier et al. (1989) and Liyanage et al. (1993) fonnd that grapes contained large quantities of glntathion—up to 300 mg/1. Although the mechanisms for this compound s accumulation in grapes have not yet been fully elucidated, the vine s water and nitrogen supply are apparently decisive factors. 

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