Processes of pistachio processing in Iran

After Iran, the United States of America, Turkey and Syria are the largest producers of pistachios in the world, respectively. In Iran, the regions of Khorasan Razavi, Rafsanjan, Kerman, Yazd, Sirjan, Fars, Qazvin and Semnan are among the major producers of pistachios. Generally  pistachios are planted in the greenhouse and after one year they are permanently transferred to the gardens. The optimal planting distance of each tree to the next tree is 7 to 8 meters, but in Iran they are planted with a distance of 3 to 4 meters. Pistachio trees start producing pistachios after 5 to 7 years and when pistachio trees are 20 to 50 years old. They have maximum production.

pistachio-kernel harvesting time starts in late summer and early autumn. In Iran, pistachio harvesting is manual and traditional, because pistachio trees have more than one trunk, mechanical harvesting is not done.

Traditional method: In the traditional method, pistachios are collected manually by workers, then they are transferred to pistachio recording terminals for processing. Fresh pistachios should be mechanized or placed in more favorable conditions after picking them from the tree about 7 to 8 hours later so that they do not rot.

Unlike Iran, pistachio harvesting in the United States of America is done with industrial machines.

Pistachio processing steps in Iran:

Fresh pistachios are processed in Iran in three ways.

In a traditional way 1

2: In a semi-mechanized way

3:In a fully mechanized way

In the traditional method, pistachio processing is mostly done manually by workers, and the only device used in this method is a peeling machine. In this processing method , the amount of fresh pistachio is small. , that's why it is also known as traditional and home units.

Fresh pistachios are processed in a semi-mechanized method by industrial equipment and finally, after passing through the dehumidifier, they are widely spread under the sunlight to dry.

But unlike the previous two methods, in the fully mechanized method, all steps, even the drying step of fresh pistachios, are done industrially.

Steps of the pistachio processing machine:

1: Peeling

2: Washing and cleaning

3: Floating tanks (Water pool)

4: Gugir

5 : Dehumidifier

6: Separation of small pistachios

7: Removal of emoty pistachios

8: Separation of closed mouth  pistachios

9: Inspection line

10: Drying

Peeling: The first stage of pistachio processing is peeling. In this stage, the pistachios that are empty,  unripe  and have aflatoxin virus are separated from the rest of the pistachios. Two types of peeling machines can be used:

Metal peeling: Metal peeling is a device that includes a rotating hub. Metal peeling consists of two parts:

A: Shear peeling: In this machine, fresh pistachio skins are cut after hitting the sharp blades and separated by a sharp device, then the pistachios that have been separated from the skin are removed from the front of the machine, and the rest of the pistachios that have not been peeled go through a cylindrical circulation. that occurs inside the device, they go back and may be repeated again and again.

Abrasion Peeling: This machine is for the pistachios that are  separated from the cluster  and in this machine the  pistachios are peeled by rubbing with a sharp object. If we put pistachios with its cluster  in this machine, it will not work and it is better to do it without clusters.

Rubber peeling: In this machine, unlike the metal peeling machine, plastic is placed on its rotor instead of metal screws. This machine does not apply much pressure to peel the pistachios, and this is good because it reduces the amount of empty pistachios, unripe pistachios and pistachios that have aflatoxin virus.