Polyphenols produced during red wine ageing

Abstract

Over the past few years, it has been accepted that a moderate red wine consumption is a factor beneficial to human health. Indeed, people of France and Italy, the two major wine-producing European countries, eat a lot of fatty foods but suffer less from fatal heart strokes than people in North-America or in the northern regions of Europe, where wine is not consumed on a regular basis. For a time, ethanol was thought to be the "good" chemical species hiding behind what is known as the "French paradox". Researchers now have turned their investigations towards a family of natural substances called "polyphenols", which are only found in plants and are abundant in grapes. It is well known that these molecules behave as radical scavengers and antioxidants, and it has been demonstrated that they can protect cholesterol in the LDL species from oxidation, a process thought to be at the origin of many fatal heart attacks. However, taken one by one, it remains difficult to demonstrate which are the best polyphenols as far as their antioxidant activities are concerned. The main obstacle in that kind of research is not the design of the chemical and biological tests themselves, but surprisingly enough, the limited access to chemically pure and structurally elucidated polyphenolic compounds. In this article, particular attention will be paid to polyphenols of red wine made from Vitis vinifera cultivars. With respect to the "French paradox", we address the following question: are wine polyphenolic compounds identical to those found in grapes (skin, pulp and seed), or are there biochemical modifications specifically taking place on the native flavonoids when a wine ages? Indeed, structural changes occur during wine conservation, and one of the most studied of those changes concerns red wine colour evolution, called "wine ageing". As a wine ages, it has been demonstrated that the initially present grape pigments slowly turn into new more stable red pigments. That phenomenon goes on for weeks, months and years. Since grape and wine polyphenols are chemically distinct, their antioxidant activities cannot be the same. So, eating grapes might well lead to beneficial effects on human health, due to the variety and sometimes large amounts of their polyphenolic content. However, epidemiological surveys have focused on wines, not on grapes....

Reduced plasma homocysteine in obese red wine consumers: a potential contributor to reduced cardiovascular risk status

“…Lower homocysteine concentrations, in addition to the antioxidant effects of polyphenols (Brouillard et al, 1997), may confer the red wine consumer a beverage-specific advantage. Severely obese patients are at considerable risk of cardiovascular morbidity and mortality.…”

Wine and health: state of proofs and research needs

“…Anthocyanins confer colour to red wines, while flavan-3-ols and non-flavonoids are generally colourless. However, chemical interactions between anthocyanins and flavan-3-ols and non-flavanoid wine components occur during wine ageing and are critical to colour stability through the formation of co-pigments (Brouillard et al, 1997;Brenna and Pagliarini, 2001;Darias-Martin et al, 2002;Brouillard et al, 2003;Boselli et al, 2004). Importantly, co-pigment formation is a feature of fine red wines that allows for ageing without loss of desirable flavour and mouthfeel attributes.…”

Influence of Saccharomyces cerevisiae strains on wine total antioxidant capacity evaluated by photochemiluminescence

“…Vineyard factors, such as grape variety, quality, climate, geographical origin and disease pressure, affect the phenolic compounds that accumulate in grapes (Siemman and Creasy 1992;Price et al 1995;Brouillard et al 1997;McDonald et al 1998). During the vinification time numerous factors, such as skin contact, temperature, presence of seeds and enzymes, have been reported to affect the extraction of phenolic compounds into fermenting grape juice (Ramey et al 1986;Kovac et al 1992;Mattivi et al 1995).…”