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Products from Grape |
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 Raisins |
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Dried grapes are otherwise known as raisins. It is one of the end products of grapes, we can’t categorize this under processed but at the same time we can’t say it is not processed, so it is considered as a semi processed grape product.
About 90% of raisins produced globally are made by drying Thompson Seedless grapes and its clones. The grape bunches are treated with grape drying oil before drying. This oil is prepared by adding 15ml ethyl oleate and 25 g potassium carbonate in one liter of water. Various countries make use of "Drying on Vine (DOV)" practice for grape drying.
While drying, water in the grape berry moves to the cuticle through the cells and then passes as vapor through the wax platelets and escapes from the outer surface. For faster drying of grapes high air temperature, rapid air movement and lower relative humidity are the climatic conditions required. For larger berries and thicker skins, the drying time is much higher. Green colored raisins fetch more price than the dark brown colored. The color depends on the drying temperature, presence of sunlight and humidity.
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| Raisins with moisture content of 12-15% are well suited for storage. During storage, low moisture raisins become hard and high moisture raisins loses its quality. Raisins are generally packed in plastic bags, in bulk quantities it is packed in cartons or tins. Usually when you pick raisins from a super market it will be packed in a plastic bag. |
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Grape Wine |
Wine is one of the major processed products of grapes. Fermentation is the process through which wine is produced. This process is initiated by adding yeast with must (red wine) or juice (white wine). During fermentation, sugar contained in the must/juice is transformed to alcohol with output of carbon di-oxide. Between 4 °C and 36 °C, yeast fulfills its task and the process stops when the sugar transforms completely. The process can even be stopped artificially by lowering the tank temperature.
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Wine gets its color from the grape skins and similarly rose wine and white wine can be made from the juice of red grapes and white grapes respectively. For making red and white wine, the suitable temperature for fermentation is 15-17 and 18-22 °C and it’s usually stored in steel or oak containers
The fermentation process lasts only a few days for lighter wines and up to 30 days for stronger wines. Based on the contact of the juice with the skins, the color and the tannin content gets stronger. This gives a longer lifespan for the wine however too much of tannins can ruin the wine. Red wines are separated from the skins and seeds and then their aging process starts in barrels and later bottles. Since white wine are fermented without maceration, white wines differ from red wines in terms of color and has lower tannin content, lighter body, a higher acidity and short aging time.
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The way the wine has been packaged has not changed much, till now. But in the last two decades, manufacturers have introduced new packaging methods to pack wines. The packaging includes pet bottles, bag in box, tetra pak, and glass bottles. These glass bottles are not the general one what we have come across, they are modified and made in different shapes and colors and at the same time made in lighter weight. |
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Grape Juice |
Another processed product of grape includes grape juice. It is very refreshing and healthy at the same time. Processing of grapes into juice is not that simple task; it needs expertise to get the right flavor, taste and color. The quality of a juice depends upon the sugar level, acid content and flavor constituents. The composition of a juice varies from year to year and changes during ripening. Several factors which influence the composition of a juice are soil, climatic conditions, biotic, abiotic stress and vineyard management practices. Grape juice gets its color from the anthocyanin pigments located in or near the skin. Grape juice is usually extracted using a hot-press or a coldpress technique and the temperature have a significant effect on its quality. Hot press techniques yields more juice than coldpress.
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Increased extraction temperature increases the color of the juice. To obtain a good color and flavor, the grapes are crushed and mixed with polygalacturonase and SO2, followed by holding it for 24hr at room temperature before low temperature extraction. Chilled, ready to serve drinks have special packaging requirements. For more than 20 years the preferred and best packaging material for these kind of juices are paper board cartons. It tastes great and is safe and healthy to consume. Generally these kinds of drinks are refrigerated all along. They are best when served chill. |
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Vinegar |
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In French, Vinegar means sour ("aigre") wine ("vin”). Vinegars can be produced from various raw materials. Converting a good wine to vinegar might be considered as waste by someone but considering the economic reasons this could also be a profitable plan. High quality vinegars are most preferred than the wines from which they are produced. |
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Sweet spreads (jam, jelly, butter and marmalade) |
The process of making these sort of spreads that is jam, marmalade, jelly and other such sweet preserves, involves the cooking of grapes and their juice in combination with sweeteners and pectin’s to the proper solids level. Jam, preserves and grape butter are made from whole or crushed fruits. Preserves generally differ from only in that the fruit pieces are usually larger. Fruit butter is made from cooking the cleaned fruits (skin and seeds removed) to a smooth silky and thick consistency. It differs from jam in its ratio of fruit to sweetener and in the final solids concentration. Jelly is made from the fruit juice so that the product is clear and firm enough to hold its shape when removed from the container.
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Jams, preserves and grape butter are made from the crushed grapes and grape juice. It consists mainly of the fruit solids and the pulp of the fruit, where the seeds and skin are removed completely. These kind of sweet spreads are generally packed in plastic boxes or tins. They come in different sizes, ranging from sachets to large tins.
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