ABSTRACT
The  study  sets-out  to  investigate  the  amount  of  some  selected  class  of  polyphenols  with cardiovascular  benefits,  present  in red wine.  The total phenolic  content of the freshly opened red wine samples  as determined  by Folin-Ciocalteau  Method  (FCM)  were  in the range  of 42-1625 mg/1 Gallic Acid Equivalents  (GAE) (Mean= 1084.6).  Samples J and N,  which were of Spanish and  Portuguese  origins,  respectively,  contained  the  highest  concentration  of  1625  mg/1  GAE each,  while  the  lowest  concentration  was  recorded  in  sample  C,  a  wine  of Nigerian  origin. Similarly,  the total anthocyanin  concentration  of freshly opened wine samples  was in the range of  20.5-166.7  mg/1  Malvidin-3-Glucoside  Equivalents  (Mean  =  109.4),  with  sample  R  (an American  wine) containing  the highest  concentration.  The total tannin  concentration  was in the range  of 225-2387  mg/l  Epicatechin  Equivalents  (Mean=  1653.1).  Wine  Q,  a  South  African wine,  had  the  highest  concentration  of tannin.  The  effect  of  air  exposure  resulted  in  a time• dependent  decline  in the total phenolic  concentration  of the wines,  with the decline  being more pronounced  after 60 mins of air exposure.  Red wine samples  with lower phenolic  concentration were found to be less affected  by the reduction  in total phenol due to air exposure.  The maximum loss  in the  total  phenolic  concentration  on  air exposure  was recorded  in  sample  S  (a  Spanish wine), whose phenol content decreased by as much as 87.4% after 120  mins.  Maximum  decrease in total anthocyanin  content  was observed  in sample A (a Spanish wine) which decreased  by as much as 58.5% after 120  mins.  Total tannin was found to be more stable than other polyphenolic compounds  present  in the  samples,  as the  total  tannin  concentration  showed  a less significant reduction  over  time.  Tannin  concentration  of sample  B  (an  Australian  wine)  and  sample  C, decreased  by  as  much  as  22%  over  the  course  of  120  mins.  A  similar  trend  in  decline  was observed during cold storage between  5-8C  after 96 hours at 24-hour  intervals.  Sample K lost as much as 87.6% of its total phenolic  content  after 96 hours.  A maximum  loss of74.9%  of the concentration  of total anthocyanin  was observed  in wine C.  For total tannin,  a loss of 47% was observed  in wine B after  120  mins.  The result  of the organoleptic  (sensory)  evaluation  and the total phenolic  concentration  were non-significantly  correlated,  r = 0.29, p < 0.05. Likewise,  there was a non-significant  correlation  between the result of the organoleptic (sensory)  evaluation  and the total tannin concentration,  r = 0.39, p < 0.05. Total phenolic  concentration  and the retail price were  significantly  correlated,  r = 0.55, p  < 0.05.  Similarly,  Total  tannin  concentration  and the retail price  were  also significantly  correlated,  r = 0.50, p  < 0.05. Comparing  the total phenolic content of the alcoholic  (M = 1201.60,  SD= 357.59) and non-alcoholic  brands (M = 967.50,  SD = 521.34),  showed a non-significant  difference  t (18) = 0.26, p  < 0.05 (p > 0.05).  In conclusion, the various wine brands differed  widely in their content of all classes of polyphenols  tested.  The polyphenols  in the samples  also differed  in their  susceptibility  to oxidation  during  air exposure and  cold  storage  after  opening.  These  observations  could  be  useful  to  consumers  who  are interested  in wines  because  of their  content  of polyphenols, which  are reported  to offer  some health benefits.
CHAPTER ONE
INTRODUCTION
Epidemiological studies have shown that a moderate wine consumption has beneficial effect on health. Wine consumption reduces the susceptibility of low density lipoprotein (LDL) to oxidation which is important for the prevention of arteriosclerosis development (Harbome and Williams, 2000; Heim et al., 2002). The practice of wine consumption has a favorable influence on the reduction of cancer incidence and on chronic inflammatory diseases, the development of both being associated with oxygen free radical (Scalbert et al., 2005). This has gained more awareness through the famous “French Paradox” which observed low death rates resulting from coronary heart disease (CHD) despite high intake of dietary cholesterol and saturated fat (Renaud and de Lorgeril, 1992). The more remarkable health promoting effect of wine in comparison to alcohol alone (in addition to other factors) is due to some biologically active compounds, present especially in red wine. Among alcoholic beverages, red wine has been reported to be more protective against coronary heart disease than other alcoholic beverages (Gronbaek et al., 1995). More than 500 different compounds, of which 160 are esters, have been
identified in different wine types. These include water (7487%, w/w), ethanol (10 14%),
saccharides  (0.05-10%),  organic acids (0.05-0.7%),  phenols  (0.01-0.2%),  and glycerol  (Soleas et al., 1997).  Phenolic  compounds  have long been considered  to be basic  components  of wines and over 200 compounds  have been identified.  The concentration  of total phenolic  compounds  in commercially  available  red wines  is rarely  above 2.5 g/1 (Singleton  et al.,  1999). Two primary classes of phenolic  compounds  that occur in grapes and wine are flavonoids  and non-flavonoids. Flavonoids  commonly  constitute  > 85% of the phenolic  content  (2:  1  g/1)  in red wines.  In white wines,  flavonoids  typically  comprise  <  20% of the  total  phenolic  content  (<  50 mg/1).  Their
dietary  intake  has  been  shown  to  be  inversely  related  to  coronary  heart  disease  mortality
(Hoffmeister et al., 1999).
Phenolic compositions is an important aspect in high quality red wines, and are responsible for astringency and bitterness (Margaret et al., 2007), and play a role in colour stability. The phenolic profile of a wine has been shown to be influenced by different viticultural practices, as well as different enological techniques. The variety, vintage and region where the grapes are grown all affect the phenolic composition of the wine (Brossaud et al., 1999; Yokotsuka et al.,
1999). The amount of flavonoids extracted during vinification is influenced by many factors, including temperature, mixing, parameters of the fermentation vessel, duration of skin maceration, ethanol concentration, SO, yeast strain, pH, and pectolytic enzymes (Brossaud et al., 1999). The concentration of phenolic compounds in wine increases during skin fermentation and subsequently begins to decrease as phenols bind with proteins and yeast hulls (cell remnants), and precipitate. During fining and maturation, the concentration of phenolic compounds continues to decrease. Their concentration is further substantially decreased at aging and cold storage (Stratil et al., 2008). Research on non-enzymatic wine oxidation by exposure to atmospheric oxygen has been approached on two major scales; from a macroscopic point of view, and a step-by-step mechanism involved in oxidation. This advanced exploration of oxidation phenomena in wine has been largely undertaken since the beginning of the 1990s (Atanasova et al., 2002). However, while detrimental effects of excessive and prolong exposure are well established, little is known about the exact impact on wine quality due to low and short levels of oxygen exposure.
1.2 Wine
Wine is  an alcoholic  beverage  (containing  ethyl  alcohol,  which  is  commonly  referred  to as ethanol) made  from fermented grapes or  other  fruits.  Wine  is  a  complex  liquid.  Although water,  ethanol,  glycerol,  and various  organic  acids  comprise  the  major  portion  of wine,  the distinct identity comes from the organic compounds (such as terpenes, esters, and alcohols), polysaccharides  and phenolics  (such as anthocyanins  and tannins) present  in the wine (Eti~vant,
1991). Some aromatic compounds are present in the grapes from which the wine is made, and some are synthesized as by-products of fermentation by the yeast that turns the sugar in the grape must into ethanol. Still others are formed only after wine has been aged and are the result of oxidation and acid-catalyzed reactions (Peyrot des Gachons and Kennedy, 2003).
Polysaccharides are polymeric un-fermentable sugars that lend body and viscosity to a wine.
Without them, a wine might seem thin or watery. These compounds are formed during fruit ripening when the grape berry softens. The riper the grape, the more these components are found in the final wine (Goldberg, 1995). Polyphenolic compounds are widely distributed in vegetables and fruit trees. They are present in complex polymeric and glycosidic forms, that could not easily be degraded by digestive juices and so their absorption could be limited. In wine, during fermentation, these aggregates are broken down to monomeric forms (Peyrot des Gachons and Kennedy, 2003). The alcohol content of 10% or more contained in most table wines gives stability to phenols present in bottled wines, allowing their absorption (Goldberg, 1995).
1.2.1 Classification of Wine
Wines are grouped by employing  a number  of different  methods. They could be grouped  into different classes by grape variety, region of origin,  colour, production technique, by the name of the wine maker or viticulturist (Liger-Belair,  2005).  For the consumer,  basically three (3) main
classes of wines  are most  easily discernible:  table wines,  sparkling  wines,  and fortified wines. Table wines (still or natural wines) make up the majority of wines available in the market.
1.2.1.1 Table Wines
Table wines contain between 10 and 14 percent alcohol and are traditionally consumed as part of a meal.  They are further grouped by their colour,  sugar content,  the variety and origin of the grapes that were used (Don~che,  1993). Wines can be white, red, or pink in colour, depending on the grape variety and wine-making technique.  Most of the table wines made fit for consumption are fermented until they are dry-this  means that,  the entire grape sugar moiety present  in the grape must has been turned to alcohol by the yeast. Off-dry (slightly sweet) wines are made by stopping the fermentation before all the sugar is converted or by adding grape juice to the wine afterwards.  In  other wine-producing regions  outside  of Europe,  California  and  Australia  in particular, table wines are most times classified by the grape variety from which they are made (Cerdan et al.,  2002).  As a rule,  at least  75 percent of the grapes used in the production of the particular wine must be of the named grape variety (Don~che,  1993).  For example,  Chardonnay is  wine  made  from  at  least  75 percent  chardonnay  grapes.  Wines  classified  this  way  are sometimes called varietals,  and include wines such as Riesling,  Cabernet sauvignon,  and Merlot. The traditional European classification system puts more emphasis on the region or appellation; where the wine  is from.  The French system of Appellation  d’Origine  Control~e  labels wines according to their geographical pedigree (Cerdan et al., 2002). The most famous wine-producing regions in France, and probably in the world, are Burgundy, in central France, and Bordeaux, a region  on the  southwestern  coast  of the  country.  Bordeaux  ranks  its  best  wineries,  called chdteaux,  and their  vineyards-crus,  into  five classes  called grand  crus:  Ch~teau Margaux,
Ch~teau Latour, Ch~teau Mouton-Rothschild and Ch~teau Lafite-Rothschild in Pauillac, plus Ch~teau  Haut-Brion  in  Graves.  Wines  from  these  vineyards  in  France  are considered  to  be among the highest-quality wines in the world (Prectorius and Hoj,  2005).
American wineries use a tag on their wine bottle labels called Appellation of Origin to indicate where the grapes were grown. An appellation can be a country, state, county, or geographically defined as American Viticultural Area (AVA). At least 85 percent of the grapes used to produce the wine must be from the viticultural area stated on the label (Don~che, 1993). The United States currently recognizes about 150 AVAs, distinguishable by geographical features. The largest growing region in the United States, California, has at least 85 AVAs, including the Napa and Sonoma valleys (Don~che, 1993).
1.2.1.2 Sparkling Wine
Sparkling wine is a modification of table wine by subjecting table wine to a second fermentation. The wine maker achieves this by adding a measured amount of sugar and fresh yeast to the dry wine (Liger-Belair, 2005). This can be carried out in a closed tank, or directly in the bottle. French champagne, the most famous sparkling wine, is produced in this way (Liger-Belair,
2005).  The fresh yeast ferments the freshly added sugar,  but this time the carbon dioxide gas remains in the sealed bottle, creating carbonation.  The basic material is usually a dry white, rose, or red table wine.  Sufficient sugar is added to the basic wine to produce a pressure of about five (5) or six (6) atmospheres. The gas bubbles to the surface when the sparkling wine is poured into a glass  (Pernot  and Valade,  1995).  Under the Appellation  d’Origine  Control~e  system,  only sparkling wines produced in the Champagne region of northeastern France can officially use the name  champagne.  Sparkling  wines  produced  in  all other  regions  of the  world,  even  those
produced  using  the  traditional  champagne  method,  are  simply  referred  to  as  sparkling  wines
(Pemot and Valade, 1995).
1.1.1.3 Fortified Wines
Fortified wines contain additional alcohol and are usually consumed in small amounts as aperitifs before meals or dessert wines after a meal (Cristovam and Paterson, 2003). Two (2) famous examples are port and sherry. In port (originated in Portugal) wine making, the grapes are crushed and the fermentation started but then stopped through the addition of more alcohol, which as a result kills the yeast. The resulting wine is sweet and has an alcohol content that is about 5-10% higher than table wine. Fortification has two purposes: (1) to raise the alcohol content sufficiently (usually 17-21 %) to prevent fermentation of all of the sugar and (2) to produce types with a special alcohol character. The alcohol used for fortification is usually (legally required in most countries) distilled from wine (Cristovam and Paterson, 2003; Liddle and Boero, 2003). The distillation of the fortifying spirits is made to a high percent alcohol, usually 95-96%. Industrial alcohol has also been employed in a few countries. Sherry (originally from Spain) is likewise produced by adding alcohol to a young dry wine in an oak barrel intentionally filled only halfway. Special yeasts called flor yeast grow on the surface of the wine and create the distinct nutty flavour characteristic of sherry (Martinez et al., 1998).
Brandy is produced from wine but is classified as distilled liquor, not as wine. Â Brandy is distilled from wine to concentrate the alcohol in the wine. After distillation the brandy is aged. Bottled brandy typically contains 40 percent alcohol and has been aged in oak barrels for several years (Singleton, Â 1995; Bertrand, 2003; Cantagrel, 2003)
1.2.2Â Â Â The Wine Grapes and Vineyards
The main grapevine cultivated for wine production  is the European wine grape is Vitis vinifera which probably  originated  in the Caucasus Mountains  (Aguero et al.,  2006).  Today there are more than 5,000 varieties  of Vitis vinifera grown  in the world  basically  localized  along the Black,  Caspian,  and Mediterranean seas.V. labrusca and V.  rotundifolia have been domesticated in the eastern United States,  the domestication of V.  amurensis has been reported in Japan,  and various interspecies hybrids have been used for wine production (Aradhya et al.,  2003). The high sugar content of most V.  vinifera varieties at maturity is the major factor in the selection of these varieties for use in much of the world’s wine production.  Their natural sugar content,  providing necessary material for fermentation,  is sufficient to produce a wine with alcohol content of 10 percent  or higher;  wines  containing  less alcohol  are unstable  because  of their  sensitivity  to bacterial  spoilage (Bertsch et al.,  2005).This grape plant prefers warm,  dry summers and mild winters,  and successful cultivation is limited only to temperate climates in both the northern and southern  hemispheres.  One  of the  major  factors  attracting  wine  makers  to  this  grape  is its tremendous range in composition  (Bertsch et al.,  2005).  The pigment pattern of the skin varies from light  greenish  yellow to russet,  to pink,  red,  reddish  violet,  or blue-black;  the juice  is generally colourless,  although some varieties have a pink to red colour,  and the flavour varies from quite neutral to strongly aromatic (examples include Gewiirztraminer,  Cabernet Sauvignon, and Zinfandel).  Some varieties, such as Pinot Noir, having rather neutral flavoured juice, develop a characteristic flavour when fermented on the skins and aged (Bouquet et al.,  2006). The species V.  labrusca and V.  rotundifolia seldom contain sufficient natural sugar to produce a wine with alcohol  content  of 10 percent  or higher  and  additional  sugar  is usually  required.  The  most popular red varieties in the United  States  are zinfandel,  cabernet  sauvignon,  grenache,  merlot,
and pinot  noir.  The  most popular  white  grapes  are  colombard,  chardonnay,  cheninblanc,  and sauvignon  blanc. Factors  associated  with  a particular  region  or areas make the wine  from that location  unique  (Bowers  and  Meredith,  1996).  These  factors  (terroir)  include  local  climate (rainfall,  sunlight  and  temperature),  location  of grapevines  (altitude  and  slope),  and  soil
(structure, composition, and water drainage). From studies, it has been observed that a grapevine
produces the best of its fruits when the moderate climate provides much sunshine and cool nights without frost, and the soil is well drained (Bowers and Meredith,  1997).  Grapevines grow best in sandy, chalky, or rocky soils. Wine grapes are grown in vineyards, where individual vines are cultured and nurtured on a system of stakes and wires,  called a trellis,  to maximize exposure to the sun.  The first harvest of grapes can be collected in the third year after the planting,  and a full crop suitable for commercial use can be expected after five years (Bowers and Meredith, 1997). Grapevines may produce fruit for 20 to over 100  years.  The grapevine growth cycle begins in early spring when new shoots appear on the buds of the grapevine.  Grapes begin their growth cycle in the spring when average daily temperature  is about  10° C (50° F).  To reach maturity, they require a certain amount of heat above 10°  C during the growing season.  This amount of heat,  called the heat summation,  is calculated by totaling the number of degrees of average daily temperature  over  10° C for each  day of the growing  season  (Fanizza  et al.,  2005).  A heat summation of about 1,800°  is required for successful growth.  If the heat summation is less than required,  the  grapes  will not  ripen;  they  will  reach  the  end  of the  growing  season  with insufficient  sugar  and too  much  acidity  (Franks  et  al.,  2002).  This  condition,  frequently occurring in the eastern United States, Switzerland, and other cool regions, can be corrected by adding sugar to the crushed grapes.  Where the heat summation is much greater than required,  as in Algeria and parts of California, the grapes mature earlier and with less acidity and colour than
those  produced  under  cooler  conditions  (Maletic  et al.,  2004).  The grapes begin to ripen  in midsummer and are ready to be harvested in midfall, depending on the location, grape variety, weather,  and the type of wine to be produced.  By the end of fall,  the vines lose their leaves and become dormant until the following spring.  The particular character of wine is strongly affected by viticultural practices such as training,  trellising,  harvesting,  and pruning (Prectorius and Hoj,
2005).  Training and trellising  enable the viticulturist  to control the sun exposure to ensure an even grape ripening.  Grapes harvested when they are not ripe may be low in sugar and may not ferment properly.  On the other hand,  overly ripe  grapes  are very high  in sugar  content  and produce wine high in alcohol (Regner et al.,  2000).  Once the vines are dormant, the viticulturist prunes the vines to remove all the dead wood. Pruning enables the grower to control the size and shape of the vines,  and also the number  of buds that will develop the next year. Just as plants have  pests  that  affect  the  quality  and  number  of  their  products,  grapevines  in  like manner have many natural enemies:  insects,  molds,  bacteria,  viruses,  and animals such as deer and birds that eat the young shoots or the sweet grapes (Regner et al.,  2000).  These pests will affect the produce from the grapevine and can as well contaminate the wine due to by-products of metabolism as remnants  from these pests.   Certain soil-borne pests,  such as the root louse Phylloxera,  destroy the roots of European grapevines.  Vines native to North and South America have a natural resistance to this insect, but they often produce grapes with an undesirable flavour (Bowers and Meredith,  1997).  To circumvent this problem,  American vineyards use grapevines grown from two different parts:  the roots from resistant American vines and the part above the ground from European  vines by a process known  as grafting  and works  much  like healing a “broken bone”.  There are about 8 million hectares (20 million acres) of vineyards in the world producing 69 million tons of grapes each year. About 29 billion liters (8 billion gallons) of wine
are made from those grapes.  Countries that produce large quantity of wine include  France,  Italy, Germany,  the  United  States,  Australia,  and  South  Africa.  Many  other  countries  produce enormous  quantities  of  table  wines  (Bowers  and  Meredith,  1997).  In  Europe  there  are,  for example,  Spain,  Portugal,  Switzerland,  Hungary,  Romania,  Bulgaria,  Greece,  and  Georgia.  In North Africa and the Middle East there are Algeria,  Tunisia,  and Israel. In South America there are Brazil,  Peru,  Chile,  and Argentina.  The  largest  wine producers  worldwide  are  France  (19 percent),  Italy (17 percent),  and Spain (13 percent).  The United  States  of America  (USA) is the fourth largest  producer  in the world,  producing  about  9 percent of the world’s  wine.  California produces  90  percent  of  all  the  wine  in  the  United  States,  with  enologists  in  New  York, Washington,  Oregon,  and at least 41  other states making the remainder  of U.S.  wine.  In Asia the largest producer is Japan ((Bowers and Meredith,  1997; Fanizzaet al.,  2005; Franks et al.,  2002).
1.3 Red Wine
Red wine is a type of wine made from dark-coloured grape varieties. Its colour can be derived from a vast assortment of grape varietals ranging from grapes that are reddish, deep purple, and even a beautiful blue on the colour scale (Boulton, 1996). These grapes give rise to a wine that is colour classified with such descriptors as garnet, almost black, dark red, light red, ruby red, opaque purple, deep violet and maroon. The actual colour of the wine can range from intense violet, typical of young wines, through to brick red for mature wines and brown for older red wines. It is the grape skins that are responsible for the red wine’s distinct colour spectrum. The skins are in contact with the grape’s juice during the fermentation process, allowing the dispersion of both colour and tannins (Bird, 2005).The juice from most black grapes is greenish• white; the red colour comes from anthocyan pigments (also called anthocyanins) present in the skin of the grape; exceptions are the relatively uncommon teinturier varieties, which produce a xxiii
red coloured juice. Much of the red-wine production process therefore involves extraction of colour and flavour components from the grape skin (Jeff, 1999). The individual wine’s particular red hue depends on the grape type used in the process and the length of time the skin’s pigmentation is in contact with juice. There are right around 50 key red wine varietals that consistently manifest themselves in today’s worldwide wine market.
1.2.1 Red Wine Styles and Varieties
Red wines are made into a variety of styles. The stylistic differences are based on differences in wine characteristics such as grape variety, colour, flavour, body, mouth-feel, and aging potential. The styles range from simple, fruity, fresh, light coloured blushes and roses to complex, full bodied, rich and dark red, with long aging potential. Many factors such as a variety, soil, climate, growing conditions, and viticultural practices influence the fruit composition, and therefore, the style of wine that can be produced. In addition to fruit composition, winemaking techniques also play an important role in determining the wine style.
Many varieties are available for red wine production. The wines are usually produced as varietals, or as blends containing several varieties. A list of commonly used red wine varieties is given in Table 1.
Table 1: Commonly Used Red Wine Varieties
VINIFERA GROUP LABRUSCA FRENCH HYBRIDS OTHERS
Cabernet Sauvingnon Concord
Baco Noir
Northon/Cynthiana
Merlot
Pinot
Steuben
Chambourcin
Chancelor
St. Vincent
Vincent
Zinfandel Syrah (shiraz) Grenache Cabernet Franc Barbera
Gamay
Foch Rougeon Villard no ir colobel
Source: Bird, 2005
Varieties from the Vinifera group are most widely used for winemaking (Bird, 2005). In regions where Vinifera  grapes are not grown,  French hybrids,  Labrusca,  and other varieties  are often used. Among the Vinifera group, Cabernet Sauvignon alone, or in combination with Merlot or Cabernet Franc is used in premium red wine production (Boulton,  1996).  Pinot noir,  the famous grape of Burgundy,  makes excellent red wine.  When grown in other parts of the world, the wine does not always attain the same level of quality as found in Burgundy. Zinfandel, though popular for blush wine, can also make dark, full-bodied, and flavourful red wine (Jeff, 1999). Syrah, the popular  grape of Rhone and Australia  makes fruity wines with softer tannins.  Concord  is  the leading red  wine  variety  among  American  grapes.  Wines  from these  grapes  have  a strong flavour,  which  is often  referred  to  as a “foxy”  aroma.  Another  American  red  wine  grape, Cynthiana/ Norton,  does not have the foxy aroma and can make full-bodied,  dark red wines (Bird, 2005). Among the varieties in the French hybrid category, Baco, Chambourcin, Foch, and Rougeon are commonly used for red wines.  These varieties,  with proper handling,  make good red table wines.  Fresh grapes make the best raw material for making red wine (Boulton,  1996). In a situation where fresh grapes are unavailable,  frozen grapes or grape concentrate can be used, particularly for making smaller lots of wine (Jeff,  1999
1.4 Phenolics
Phenols are a large and complex group of compounds of pnmary importance to the characteristics and quality of red wine. They are also significant in white wines, but occur at much lower concentrations (Waterhouse and Edeler, 1999). Phenols and related compounds can affect the appearance, taste, mouth-feel, fragrance, and antimicrobial properties of wine. Although primarily of grape origin, smaller amounts may be extracted from wood cooperage. Only trace amounts are derived from yeast metabolism (Waterhouse and Edeler, 1999).
1.4.1 Polyphenols
Polyphenols also described as Polyhydroxyphenolsare a group of orgamc chemicals characterized by the presence of large multiples of phenol structural units. They are basically natural, but can also be synthetic. The unique physical, chemical, and biological (metabolic, toxic, therapeutic, etc.) properties of a particular class are characteristic of the number of these phenol structures bonding together to form the polyphenol (Quideau, 2011). The major polyphenolics found in wine are either members of the diphenylpropanoids (flavonoids) or phenylpropanoids (non-flavonoids). In addition, there are related (phenyl) compounds that do not possess one or more hydroxyl groups on the phenyl ring (and are correspondingly strictly not phenols).
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QUANTIFICATION OF THE POLYPHENOLIC CONSTITUENTS OF RETAIL SAMPLES OF RED WINE>
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