Grape juice fermentation

Reduction of tartaric is, of course, incidental to fermentation wherever wine is made. This acid, mainly present in grapes as potassium bitartrate, is much more soluble in water (the principal ingredient of grape juice) than in alcoholic solutions. Thus, as grape juice ferments and alcoholic content... 

All amino acids, except proline, may be used by Saccharomyces cerevisiae in grape juice fermentation. Amino acids can be directly used to synthesize proteins. However, the amino acid composition of the grape juice is not necessarily similar to the needs of the cell. For that reason, yeasts must use the remaining amino acids to synthesize those which it lacks (Hensche and Jiranek 1993 Ribereau-Gayon et al. 2000b). In this case, ammonia is incorporated into other amino acids whereas the carbon skeleton is metabolized by the cell. 

Succinic acid Succinic acid is quantitatively the third product of alcoholic fermentation. Some authors suggest that succinic acid is synthesised via Krebs cycle although its functioning is seriously limited (Heerde and Radler 1978). However, other authors think that this cycle is not operative in conditions of grape juice fermentation (Salmon et al. 1987). In any case, succinic acid is present in wine... 

Edwards, C.G., Reynolds, A.G., Rodriguez, A.V., Semon, M.J., Mills, J.M. (1999) Implication of acetic acid in the induction of slow/stuck grape juice fermentation and inhibition of yeast by Lactobacillus sp. Am. J. Enol. Vitic., 50, 204-210. 

Dextro tartaric acid is the ordinary tartaric acid as it is found widely distributed in nature, in grapes, mountain ash berries, pineapples, potatoes and other plants. It crystallizes without water of crystallization in transparent, mono-clinic columns which are easily soluble in water or in alcohol. 100 parts of water at 15° dissolve 132 parts of the acid. It melts at i68°-i70°. In water solution it is dextro rotatory. The chief source of tartaric acid is the juice of the grape, where it is present as the free acid and as the acid potassium salt. In this source it is mostly the dextro variety that is found. It is obtained from the vinasse, or residue which settles out from the juice after it has been expressed. When grape juice ferments, in the formation of wine, the solubility of the acid potassium salt is lessened due to the presence of alcohol and it gradually separates and settles to the bottom iii the form of what is known as lees. These lees are dried or recrystallized once and the product is then known as crude tartar or argol. The crude tartar contains, in addition to the acid potassium tartrate, free tartaric... 

Edwards, C.G., Haag, K.M., Collins, M.D., Hutson, R.A., and Huang, Y.C. 1998. Lactobacillus kunkeeisp. nov. A spoilage organism associated with grape juice fermentations. J. Appl. Microbiol. 84, 698-702. 

Oxygen is frequently limiting during grape juice fermentation. The... 

Vianna, E. and Ebeler, S. (2001). Monitoring ester formation in grape juice fermentations using solid phase microextraction coupled with gas chromatography-mass spectrometry, J. Agric. Food Chem., 49(2), 589-595. 

PiLONE, A.D., GJ. PiLONE, and B.C. Rankine. 1973. Influence of yeast strain, pH and temperature on degradation of fumaric acid in grape juice fermentation. Am.f Enol Vitic. 24(3) 97-102. 

OuGH, C.S. and A.A. Bell. 1980. Effects of nitrogen fertilization of grapevines on amino acids metabolism and higher-alcohol formation during grape juice fermentation. Am.J. Enol. Vitic. 31 122-123. 

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