Phenolic compounds grape juice

The consumption of a mixture of phenolic compounds presented in apple or purple grape juice inhibited mammary carcinogenesis in 7,12-dimethylbenzo[a]anthracene (DMBA) treated rats (Liu and others 2005 Jung and others 2006). However, the individual antioxidants of these foods studied in clinical trials, including (3-carotene, vitamin C, and vitamin E, do not appear to have consistent preventive effects comparable to the observed health benefits of diets rich in fruits and vegetables, suggesting that natural phytochemicals in fresh fruits and vegetables could be more effective than a dietary supplement. 

Polyphenols and flavonoids present in red wine and grape juice, fruits and vegetables, have potent antioxidant activity, which may slow down oxidative modification of LDL, and their subsequent toxicity (Wedworth and Lynch, 1995). Phenolic compounds exert cytoprotection on vascular cultured cells by inhibiting the calcium rise and subsequent oxidized LDL-mediated cell death (Vieira et al, 1998). These compounds may play a role in the relatively low level of coronary heart disease in Prance ( Fnench Paradox ) and other Mediterranean countries (Renaud and Ruf, 1994). 

Cheynier, V., Osse, C., and Rigaud, J., Oxidation of grape juice phenolic compounds in model solutions. J. Food Sci. 53, 1729, 1988. 

Alcohol consumption Moderate consumption of alcohol (for example, two drinks a day) decreases the risk of coronary heart disease, because there is a positive correlation between moderate alcohol consumption and the plasma concentration of HDLs. However, because of the potential dangers of alcohol abuse, health professionals are reluctant to recommend increased alcohol consumption to their patients. Red wine may provide cardioprotective benefits in addition to those resulting from its alcohol content, for example, red wine contains phenolic compounds that inhibit lipoprotein oxidation (see p. 233). [Note These antioxidants are also present in raisins and grape juice.]... 

Phenolic compounds are of interest due to their potential contribution to the taste (astrin-gency, bitterness, and sourness) and formation of off-flavor in foods, including tea, coffee, and various fruit juices, during storage. Their influence on the appearance of food products, such as haze formation and discoloration associated with browning in apple and grape products, is also significant. Furthermore, analysis of these phenolic compounds can permit taxonomic classification of the source of foods. The importance of each phenolic compound and its association with the quality of various foods is described further in Sec. IV, on food applications. 

Since phenolic compounds occur in many fruits and most of them contribute to color and taste, phenolic analysis of fruits has been an active research area, especially in apple, grape, and citrus fruits and their products, such as juice, cider, and wine. 

The phenolic compounds of grapes and wines are very important for their sensory effects as well as for their contribution to color. Grape juices and wines with higher polyphenolic concentration are more susceptible to oxidation, which can in turn lead to poor wine quality. 

Sweet and dry white wines result from the alcoholic fermentation of pure grape juice, clarified by settling. In comparison to red wines, only very small amounts of phenolic compounds are dissolved, as contact with grape solids only occurs during maceration prior to fermentation. 

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