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Grapes — Storing methods to keep grapes fresh

Origins of grape vines go back to millions of years ago, and Caucasus, south of the Caspian Sea and North East Anatolia are known as the native lands of grapes.

Storing methods to keep grapes fresh

Modern Georgia, Armenia, Azerbaijan, Iran, Anatolia and part of Russia are the regions where grapes spread to the world. The availability of many indigenous grape varieties in these regions seems to prove this estimation. Vine cultivation goes back as far as to tribal civilizations. Although it is known that development of vine cultivation dates back to 6000 BC, it is estimated that wine production began long before Over 70 million tons of grapes are cultivated all around the world. Nearly 30% of this amount is consumed as table grapes, and the remaining part is sent to the industry creating a large-scale economy. Along with their fresh consumption, grapes are used in the production of wine, molasses, fruit leather, jam, juice, vinegar, grapes seed oil and raki.

According to the data on the world table grape production, China is the leading country with a production of 9 million 600 thousand tons. China is followed by India with 2 million 500 thousand tons and Turkey with 2 million tons of production. The European Union, Brazil, Chile, the United States, Peru, Ukraine and South Africa are the other largest grape producers.

Being one of a few leading producers in the world, Turkey is also the leader and price setter of the raisin industry. The estimated number of varieties of indigenous grapes in Anatolia is more than 1,200.

Packed with plenty of vitamins B, C, E, grapes are also rich source of potassium, calcium, sodium, phosphor, iron, magnesium and sulphur. It is stated that grapes and grape juice reduces the risk of colon cancer by 50%. This healing fruit is a strong blood purifier also reducing the levels of cholesterol thanks to the inositol contained in it.

Today, many grape varieties can be stored in modern storage for longer periods. These characteristics of grapes help them find domestic and foreign markets all around the world creating a large-scale economy.

Unlike apples and pears, grapes cannot continue ripening after the harvest. Therefore, they should be harvested when they are ripe and quickly be transported to cold storage.

Storage is the key — Cantek Group

The point where the biggest intervention is required in storing grapes is a facultative saprophyte such as botrytis cinerea. Although the fact that grapes don’t continue respiration and stop ripening after the harvest provides advantage in terms of storage, preventative measures should still be implemented against botrytis cinerea. There are more than ten methods in preserving grapes, but the most commonly used method is the use of sulphur dioxide gas. Sodium metabisulfite gas is used in this method, by being incorporated into nylon sacks and papers to modify atmosphere conditions. Immediately after the harvest, grapes are filled in Modified Atmosphere Packaging and then papers absorbed in sodium metabisulfite are placed under and on top of grapes before they are stored in cold storage. Sodium metabisulfite burns by absorbing the water vapour released during the respiration of grapes. As a result of this reaction, sulphur dioxide is formed in a certain level of density. This is the most commonly used method to combat botrytis cinerea during the storage of grapes. During all these applications, characteristics of nylon sacks, papers’ expiry date, gases within the sacks and humidity levels in the room should be paid special attention. The fact that the temperature of grapes for long-term storage is lowered in pre-cooling rooms and then stacked in the main cooling room is very important and beneficial in terms of keeping their quality. Since the sugar levels of grape varieties differ when they are harvested, their freezing point also varies; therefore, the temperature should be controlled as the sugar levels increase. Grapes should be kept in polyethylene bags manufactured specifically for grapes at 1°C (33.80°F) in order to keep the quality of grapes whose temperature is rapidly lowered. After this preparation, grapes can be kept for three months with no spoilage. When these treatments are carried out with care and with the help of the experiences gained over time, grapes will be able to be kept for up to 5 or 6 months.