WHEN THE WALNUT MUST BE HARVESTED

It is deemed as the period, in which the walnut kernel and green shell ripen. Indication of walnut kernel’s maturity is the period, in which the package texture placed between the kernel and hard shell starts to get Brown. Mostly, the green shell matures later than the walnut kernel. Carrying out the harvest at the time of walnut kernel’s maturity shall increase the trade value of the walnut kernel, because the walnut kernel is in light colour in this period. However, if the cultivator waits the maturity time of the green shell, then very important quality losses may occur.

Climate may have an important impact on the harvesting time of walnut. Ripening time of the walnut kernel and the ripening time of green shell generally coincide in the regions having a cool climate. High humidity accelerates the opening of the green shell. Another important factor having impact on the harvesting time is the variety cultivated. For instance, the varieties such as Chadler and Serr have light-coloured kernel, when the harvest is made promptly and properly. Collecting the harvested fruits, separating the green shells, and drying the fruits, etc. must be made as soon as possible, in order to prevent the quality losses. Deteriorations are seen in the colour of kernel, in case of fruits remaining under the sun, and fruits, on which the green shell remains for a long time.

Harvesting Methods for Walnut;

Harvesting is carried out by hand and mechanically for walnuts. While harvesting is carried out in the form of thrashing the tree with a stick in Turkey, it is carried out mechanically in the countries, which lead in walnut cultivation. In case of harvesting through thrashing the tree, important damages may occur, primarily on the branches that shall yield in the next year. Harvesting mechanically is made in the form of shaking the main branches of the tree or the body of the tree via the different shakers, and ensuring that the fruits drop from the tree. Different shakers are used for this purpose.

Peeling off the walnut shell after harvesting;

Green shell must be separated from the hard shell easily, thus fruits must be flaked immediately after the harvest, in order to minimize the quality losses. In some of our regions, putting over covers such as nylon, thick cloth, and sacks in order to soften the green shell and to peel it off easily may cause important quality losses. In flaking procedures carried out via the machines, it is ensured that the green shell is removed without any losses.

Drying the Walnut;

Fruits, which shall not be utilized as walnut kernel, thus which shall be marketed with shell, must be dried immediately after the flaking treatment. Drying procedure is important regarding the storage life of the walnut. For this, the highest humidity rates that must be present in unshelled and kernel walnut are determined by the standards. For instance, 8% humidity rate is sought in dried unshelled walnut and 5% humidity rate is sought in walnut kernel according to TSE (Turkish Statistics Institute). Generally walnuts are dried outside in the shade in our country. In some of our regions, drying is carried out by holding them under sun for 7-10 days. This also causes various quality losses such as the darkening of the kernel’s colour. Therefore, this type of drying is wrong. In case there is not any other possibility for drying, then at least it must be carried out outside in the shade, and not under the direct sunlight. However, drying is carried out completely in mechanical ways in the countries, which lead in the world’s walnut production. In drying that is made through mechanical ways, the fruits are hold at 30-350C0 for 24 hours. Increase of the temperature above 400C is not favourable for the quality of the kernel.

Storing and Packaging;

Since the walnuts are fruits having high oil content, storing in suitable conditions is important in terms of oil degradation primarily within the content of the kernel. Therefore, walnuts can be kept for long periods at low temperatures (0-40C) and in dry environments.

Packaging is a very important stage in marketing any product. Therefore, making the packages duly with the healthy materials attracts the consumers in terms of marketing both the unshelled and the kernel walnut. A very clear difference is seen between the attractiveness of mixed walnuts, which are filled into big sacks, and of the walnuts, which are in the same colour and packed with small basis weight. For instance, packaging the walnut kernel with light-proof, vacuumed plastic bags and labelling it are very important for the consumers. Carrying out the procedures during and after harvesting correctly is one of the subjects that must be considered for the producer.

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