Plums drying (prunes).
In the production process of plums drying , the choice of raw materials is important. The flesh should be pulpy and juicy, and the pit should be small. The high content of dry substances determines the economic benefit and price of dried prunes. The production of prunes should be located within the production of raw materials and should not exceeding 200 km.
Raw materials for the prunes production are collected during technical maturity. Within this period the fruits reach their maximum size but are not yet ripe. Before plums drying the raw material passes through the preliminary preparation stage. On the inspection conveyor the damaged and unripe fruits are rejected. Next, the size calibration process takes place. Plums drying should be done separately for each caliber, as this optimizes the production process from a qualitative point of view
The plums that are calibrated according to the technology are washed in washers or shower devices. The plums are covered with a dense peel. The peel interferes with the free moisture evaporation from the fruit. To increase performance the blanching should be performed. This technological operation reduces the drying time by 6-8 hours. During blanching the wax coating is removed from peel and the cellular links are broken. This allows increasing the moisture evaporation.
In this process, the plums are first dried at high temperatures, which are further decreasing with the belt movement in the drying chamber. The initial high temperature prevents the fruits from cracking and the loss of juice.
The blanched plums are dried in the band conveyor dryers. Considering that the drying speed plums drying in the band dryer is about 12-16 hours, it is reasonable to use multi-level band dryers. The exact duration of prunes drying depends on various factors. These are dimensions, varieties, quality of equipment for preliminary preparation, etc. The high-quality prunes require a process of blanching. As a result, the product is soft, has a good marketable condition, and the sale price of such prunes is higher than of similar ones. Thus, the prune drying in industrial conditions makes it possible to produce high-quality products.
The production technology of prunes allows reducing the final moisture content of the product to 20-25%. This is enough for long-term storage. The product is packaged in cardboard boxes.