Characteristics of piraltin, a polyphenol concentrate, produced by freeze-drying of red wine.

Moderate consumption of red wine is associated with a decreased risk for coronary heart disease. Apart from alcohol, an additive role for wine polyphenols has been suggested. However, the real contribution of these compounds can only be studied when available without the alcohol component. The objective of the study was to prepare a wine polyphenol concentrate not containing alcohol and to compare the quantitative and qualitative properties of this concentrate with those of the original wine from which the concentrate is made. This polyphenol concentrate, called piraltin, was made out of red wine by a freeze-drying technique. Both piraltin and the original red wine were analyzed quantitatively for the main polyphenols present: gallic acid, catechin, epicatechin and quercetin. The qualitative comparison comprised the inhibitory effect of the two products on LDL oxidation in vitro. In the process of freeze-drying recovery of the four determined flavonoids of red wine is fairly constant (average 68 +/- 7%). In a copper induced LDL oxidation assay both red wine and piraltin prolonged lag-times over 300% compared to controls without a significant difference between the two products. The freeze-dried polyphenol concentrate piraltin contains about 70% of the total polyphenol content of the original wine. This preparation technique does not cause a loss of antioxidative properties of the phenols. Piraltin creates the possibility to study the effects of wine polyphenols separately without the influence of alcohol both in vitro and in vivo.