The grape is a fruit that grows in tight clusters. It has a white or purple flesh of sweet taste, eaten raw or in juice, although it is chiefly used for making wine. They are also used to make preserves. It contains various minerals and vitamins, and it is considered to be antioxidant and anti-carcinogenic. Grapes are fleshy, rounded fruits that grow in clusters made up of many fruits of greenish, yellowish or purple skin. The pulp is juicy and sweet, and it contain several seeds or pips. It is a well-known fruit; it is eaten raw, although it is mainly used for making wine. Raw grapes are excellent as table dessert, combined with other fruits in fruit salads. Great part of the production is intended for making wines and must, whereas from their seeds we extract the grape seed oil.
The clusters are dried to make raisins; besides, there are multiple preserves made from grapes, like caramel grapes, grape syrup, grapes in alcohol and grape jelly. Grapes supply minerals and vitamins to the organism. They are one of the fruits providing more carbohydrates, although their caloric content is not very high. They contain resveratrol, an antioxidant and anti-carcinogenic compound. From the antiquity, grapes have been given various healing properties.
Types and Varieties of Grape
There exist multiple varieties of grape, that can be classified according to their use in table grapes, for making raisins, must, for canning and those intended for obtaining wine. Within this last group are gathered the greater amount of varieties, since grapevine is mainly intended for wine production. At the same time, grapes are differentiated in red and white, according to the type of wine made with them.
Table grapes: these varieties are intended for fresh consumption. They bear large grapes, of uniform size and colour. The clusters are not compact, favouring their consumption. There are three types of table grapes: white, red and black. The best known white varieties are ‘Almería’, ‘Italia’, ‘Chasselas’, etc. Some red varieties are ‘Cardinal’, ‘Chasselas dorée’, ‘Emperor Queen’ and ‘ Moscatel roja’. Among the black varieties we find ‘Moscatel de Hamburgo’, ‘Alphonse Lavallé ‘ and ‘ Exotic’.
Grapes for making raisins: these grapes must be of smooth texture and seedless, although there are some varieties with seeds. If they are intended for direct consumption they must be large, but if they have to be used in confectionery they preferred ones are the small. The main varieties intended for this use are ‘Sultanina’, ‘Corintia negra’, ‘Moscatel de Alejandría’ and ‘ Dátil de Beirut’.
Grapes for natural juice: these varieties must keep their natural taste and aroma after the treatment they are put under for their preservation. In general, the Vitis vinifera grapes do not satisfy these requirements; the most used are ‘ Concord’ and ‘Niágara’, belonging to Vitis labrusca.
Grapes for canning: they are seedless varieties that are put along with other fruits to make cocktails and fruit salads. The most appreciated variety is ‘Sultanina’.
Grapes for making wine: it is the main use for which grapevine is intended, so there are no end of suitable varieties for wine processing. These can be classified into black and white grapes, according to the colour of the wine. In Spain, among the black ones we find ‘Bobal’, ‘Cabernet Sauvignon’, ‘Embolicaire’, ‘Forcayat’, ‘Garnacha’, ‘Tintorera’, ‘Merlot’, ‘Monastrell’, ‘Tempranillo’, ‘Pinot Noir’, etc. Among the white varieties we have ‘Airén’, ‘Chardonay’, ‘Macabeo’, ‘Malvasía’, ‘Merseguera’, ‘Moscatel’, ‘Plant nova’ and ‘Riesling’.
The grapevine belongs to the family of Vitaceous and the sort Vitis. It is cultivated forming shrubs. It is a climbing plant that has a kind of earrings to climb up. It may grow up to 17 meters high if it is not taken care of. Their leaves are alternate and lobulated, composed of five main nerves. They characterise the different varieties. The flowers, of small size, are grouped forming clusters. The petals are free in their base and joined in the apex. The fruit is a berry containing hard seeds. The size ranges from 12mm to 24mm, and varies according to the species. The shape may be spherical, elliptical, ovoid, cylindrical or bent. The colour ranges from yellowish green to black-red. In botanic, the Vitis sort is divided in two sections: Muscadinia and Vitis.
Section Muscadinia: these grapevines are original from the Southeast of the United States and the north of Mexico. Three species are known, all of them with little commercial interest: Vitis rotundifolia, Vitis munsoniana and Vitis mopenoi.
Section Vitis: this group gathers the true grapevines. There are multiple species within this section. V. candicans, V. Longii and V. champinii are American species used as rootstock. V. labrusca is an American variety whose fruit is eaten fresh or used for processing natural juice. V. Caribaeae is an original species from the tropical areas of America. It is known as ‘ water liana’ or ‘sour grape’. Some other grapevines of American origin used as understock are V. berlandieri, V. aestivalis, V. cordifolia, V. monticola, V. riparia and V. rupestris. However, the species with greater importance is Vitis vinífera, from which come the main varieties of grape used for making wine.
Origin and Production
The grapevine is native to Asia and it is well-known from Pre-history. Its culture began in the Neolithic period and it spread to the rest of Europe, arriving at the American continent. At present, the continent with larger production is Europe. The grapevine is thought to originate in the Caucasus and western Asia and it was probably already harvested in the Palaeolithic. It is certain that there existed wild grapevines during the Tertiary Age. During the Neolithic period (6000 B. C.) the culture of the grapevine was initiated in Asia Minor and the Near East. They gradually selected the species with better production, until they obtained the current grapevines, of great fruit. The Egyptians knew the grapevine, but the Greeks and the Romans where the ones who developed its culture to a greater extent, spreading it all over the Roman Europe. The Spaniards introduced this crop in North America. At present, Europe is the main producing continent, standing for half of the world-wide production of grape. It is followed by Asia. The areas with a smaller amount of grape cultivation are Africa and Oceania. Grape production, both table grape and wine grape, by continents is the following:
Source: FAO Production Yearbook, 2000
The great majority of main producers are European. The first is Italy, followed by France, the United States and Spain. The following table shows the countries with greater production of table and wine grape:
|The United tates||6,792,000|
Source: FAO Production Yearbook, 2000
The following table shows the main countries exporting grape (table and wine grape). Italy is the leader, followed by Chile, the United States and South Africa.
|The United States||280,155|
Source: FAO Trade Yearbook, 2000
Among the import countries, the United States is the first one, followed by Germany, China, United Kingdom and France.
|The United States||383,672|
Source: FAO Trade Yearbook, 2000
The time of the year to consume fresh grape starts at the beginning of summer and ends at the beginning of winter. However, nowadays some varieties of table grape are available all the year round, from different origins. They can also be consumed tinned or dried, that is to say, raisins. The following table shows the months of availability of some varieties of grape. The table also indicates the countries exporting and the weight of the packages used.
|Origin||Months of availability United Kingdom||Weight of the packages|
|Benitaka||April-June and September-January||5/8,2kg|
|Italy||April-June and September-January|
|Muscat||April-June and September-January|
|Perlette||April-June and September-January|
|Redglobe||April-June and September-January|
|Ribier||April-June and September-January|
|Ruby seedless||April-June and September-January|
|Thompson seedless||April-June and September-January|
|Crimson seedless||May-August and October-November||5kg|
|Flame seedless||May-August and October-November|
|Kingruby||May-August and October-November|
|Perlette||May-August and October-November|
|Romi||May-August and October-November|
|Sultana||May-August and October-November|
|Superior||May-August and October-November|
|Thompson seedless||May-August and October-November|
|Muscat of Hamburg||August-October|
|Red and white||September|
|Regina del Vigneti||July-September|
|Queen of the Vineyard||January-February||4kg|
|Dan Ben Hannah||January-April|
|Sun red seedless||February-April|
|THE UNITED STATES|
|Flame seedless||According to the market demands||Various|
|Sultana||According to the market demands|
Source: Fresh Product Desk Book, 1998
In the United States, grapes are usually sold in wood boxes of 11kg. Apart from these traditional boxes, plastic boxes of 0.5 to 1.5kg, painted in bright colours so as to be attractive to the consumer. The new packages try to be more comfortable and appealing for the consumer; the designs incorporate bags with only one raceme, trays with two racimes, etc.
The European Economic Community gathers the quality standards referring to table grapes in the Commission Regulation (CE) No 2789/1999 of 22 December 1999. According to these standards, the grape clusters and grains must be sound, clean, practically free of insect attacks or diseases, free of abnormal external moisture and any foreign smell or taste. The grains must be well-formed and adhered to the cluster. They must be harvested carefully and in a condition such as to enable them to withstand transport and handling and to arrive in satisfactory condition at their place of destination. Table grapes are graded in three classes according to their quality.
Extra Class: these grapes are of the best quality. The grains must be free of any defect, hard and well-joined to the cluster.
Class I: the grains of this class may be less uniform and more separated in the cluster than in the previous class. Slight deformations, slight defects of coloration or very small sun burns are allowed only affecting the skin.
Class II: these clusters may show slight defects of development, shape and colour. The grains flesh must be sufficiently firm and their distribution in the cluster may be more irregular than for Class I. They might show malformations, defects of coloration, small sun burns, light bruises and alterations of the skin.
The minimum size required in grams is shown in the following table. There is a distinction between varieties cultivated in greenhouse and outdoors. The latter are differentiated as well in thick grain and small grain varieties.
|Thick grain||Small grain|
Concerning tolerances, 10% of the bulk produce shall not fulfil the requirements of the class or the size indicated in the package, except for the Extra class, for which this percentage is 5%. The content of each bulk must be uniform and contain grapes of the same variety, class and degree of maturation. The preparation must guarantee a satisfactory protection for the produce. The materials used must be new and clean and they must contain substances that may affect the content. Each bulk must clearly bear the name of the packer, sender, the variety of grape, the origin and class.
With regard to raisins or dried grapes, the UN lays down a standard referring to the commercial quality of this produce, the UN/ECE STANDARD DF-11, for reference and non compulsory. The produce must be intact, sound, free of living insects or mites in any stage of development. It must be free from abnormal external moisture and foreign smells or tastes. Its condition must be such as to enable it to withstand transport and handling and to arrive in satisfactory condition at its place of destination. The water content must not be below 13% in any case and not over 31% for the type Moscatel, 23% for the varieties with seeds, and 18% for the seedless varieties. The additives or ingredients added to the raisins during the processing must be allowed in the country of import. Raisins are graded in three classes according to their quality.
Extra Class: these are the raisins with the best quality. They must have good characteristics of taste, texture and colour. They must have been obtained from mature grapes, practically free of defects except for some slight and very superficial defects, provided they do not affect the quality of the produce.
Class I: in this case slight defects are allowed within the ranks indicated in the tolerances.
Class II: defects within the limits indicated in the tolerances are allowed, provided they do not affect the general appearance, quality and presentation of the produce. The sizing for all classes is determined by the maximum number of grains in 100g or by the smallest diameter of the grains.
Postharvest Atmosphere Management
Table grapes must be stored at temperatures between -1 and 0ºC and 90-95% of moisture. There must be a suitable air circulation in the camera. Grapes are not sensitive to ethylene, although concentrations over 10ppm may cause the grains to separate from the peduncle. The use of modified atmosphere is not recommended, since it is hardly beneficial.
Among the different problems that grapes may undergo while stored there are some physiological alterations like watery grains or the berries fall from the peduncle. The most important disease in conservation is the one caused by the fungus Botrytis cinerea.
Grains falling: the more mature the fruit is, the worse the problem. This alteration is less frequent in seedless varieties. It normally occurs during the harvesting and handling in the field, although it also takes place afterwards. This problem may be reduced by means of a correct handling and maintaining satisfactory conditions of moisture and temperature.
Watery grains: The first symptom of this alteration is the appearance of small dark spots in the peduncles of the grains. These spots spread all over the surface. Finally, the grains affected soften and they turn watery. During harvesting and packaging these grains can be removed, although it is very tough to do so. Among the diseases affecting grapes during storage, the grey mould is the most important one. It is caused by the fungus Botrytis cinerea, that may grow at very low temperatures, even at -0,5ºC; this disease spreads from one grain to the other. At the beginning they turn into a brown colour and afterwards they are covered by a grey down. The consequences of this infection may be diminished by means of removing the affected clusters and cooling them as soon as possible. Another system is the sulphur dioxide pulverisation.
|Grape, Vitis vinifera / Fam.: Vitaceae|
| Note: Composition for 100 g. of fresh product
Values in ( min. – max. ) format.
Health Benefits of Grapes
Table grapes are a source of pro-vitamin A carotenoids, vitamin C and flavonoids (myricetin and quercetin). Grapes also contain resveratol, which is another phytochemical. A ration of 125 g supplies approximately 25 % of the daily recommended consumption of vitamin C, a powerful antioxidant that protects against various types of cancer and improves the immune functions. Vitamin A provides protection against ocular disorders, and at the same time it is beneficial for the bones development, to maintain the body tissues in good condition, for the reproduction and development of the hormonal and co-enzymatic function. Flavonoids occur among the secondary compounds of fruit and vegetables; when consumed in a varied diet, they are claimed to protect against cancer and some cardiovascular diseases.
Grapes have been employed for a long time with healing purposes. They are laxative and diuretic, specially recommended in cases of weakness or low body defences. They are good to depurate blood and they also prevent osteoporosis. In case of constipation, grapes must be eaten with the skin and the pips, whereas if they are consumed by elderly people or people with weak digestive organs they must be taken in juice. Grapes are laxative and diuretic.