How to Dry Plum Fruit/Dehydrate Plum Fruit in a Dehydrator

Jul 17, 2021

Introduction to plum fruit：

The plum fruit was picked too early, the flavor was not good, the fruit was too mature, the fruit had become soft, and could not be stored. Generally, the fruits should be harvested near the full ripe stage, and the fruits for processing should be harvested at the hard ripe stage. Plum has strong adaptability to climate and high requirements for air and soil humidity, so it should be planted in the place with loose soil and good drainage.

Plum fruit processing steps：

1. Raw material treatment
The harvested plums should be peeled first to remove the wax layer on the surface of the peel, so that sugar can easily penetrate into the pulp.
2. Hardening and color protection
There is a kind of tannin in the flesh of plum. During the processing, the tannin oxidizes and makes the product gray brown, which affects the appearance. Therefore, it is necessary to prepare the mixture of hardening and color protection; Soak the raw material with 0.1% calcium dichloride and 0.1% sodium bisulfite mixture for 8 hours, then wash it with clean water and drain the water for standby.
3. Prepare sugar solution
50 kg fresh fruit needs 25-30 kg white sugar to make 40% sugar liquid. Add 0.1% citric acid and 0.05% potassium sorbate into the sugar liquid. Boil the sugar liquid and add the raw material to soak.
4. Sugar permeation technology
When plums were immersed in sugar, the concentration of sugar decreased greatly the next day. Generally, the concentration is only about 20%, so it is necessary to concentrate the sugar liquid, extract the thin sugar liquid, and heat it in the sandwich pot or stainless steel pot for concentration. It is required to increase the concentration by about 5%, and add the concentrated sugar liquid back to the plum for soaking. After 1-2 days to repeat this process, only boiling sugar, raw materials can not be directly heated. In the process of sugar rising, it is the process of water evaporation and sugar absorption. If there is no vacuum sugar permeating equipment, the cycle is relatively long. Generally, it takes 15-20 days to make the sugar liquid rise to 55% - 60%, and the sugar liquid concentration inside the pulp is required to reach more than 50%.

Plum fruit drying process：

The 6p heat pump dryer is equipped with a drying room with a length of 5.8m and a width of 2.2M, which can be pushed into eight material trucks at a time. Each truck is loaded with 180 kg of materials, totally 1500 kg of materials. The temperature of the drying room is controlled at 60 ℃ - 70 ℃ for 20 hours, and the water content is controlled at 25-28%.

Recommendation of plum fruit dryer/drying machine

Commercial 100-3000kg/h large amount of dehydration wide application and easy operation

Heat pump drying machine use the principle of inverse Carnot cycle. It absorbs low-temperature heat energy in the air, which becomes high-temperature heat energy after efficient heat collection and integration by the heat pump system, and is transported to the drying room for cyclic heating and drying of materials.It refers to exhausting the hot and humid air in the drying room directly to the outside of the drying room through dehumidification device, and then replenishing natural fresh air.

Hot air circle drying machine belongs to high temperature heat pump unit. Its working principle is: the working fluid of the heat pump is compressed by the compressor, becomes high temperature and high pressure gas, enters the condenser, condenses and liquefies the heat, and is used for air heating in the drying room. The moisture in the material is vaporized and evaporated by the form of hot air, and the evaporated water vapor is discharged by the moisture discharge system, thereby achieving the purpose of drying the drying material.