How to prolong the storage period of fresh jujube

Jujube contains a variety of trace elements and rich nutrients, which has unique nutritional and medicinal value. However, the fresh jujube is stored under natural conditions after harvest, and the flesh will soon turn brown and soften after only a few days of fresh crisp period. After several years of experimental research, the author believes that in order to prolong the storage period of fresh jujube, we must grasp the following key technologies:

First, select storage-resistant varieties

Generally speaking, late-maturing varieties are more resistant to storage than early-maturing varieties, and dual-purpose varieties are better than fresh varieties. At present, the quality and storability of winter jujube is known as the king of jujube fruit in fresh jujube (it is generally believed that winter jujube is a late-maturing variety with a fruit growth period of more than 120 days, which usually matures in mid-late October). There are several kinds of winter jujube which are more tolerant to storage: Zhanhua winter jujube, Daxue jujube, Xuechengdong jujube, Chengwu winter jujube and September green jujube.

Second, do a good job in pre-harvest management

It is necessary to do a good job in the management of soil, fertilizer and water and the prevention and control of diseases and insect pests in jujube orchard in order to enhance the storability of jujube fruit itself. 0.2% calcium chloride solution and 1000 times methyl topiramate solution were sprayed on the crown and jujube fruit half a month before harvest to increase the calcitonin content of jujube fruit and prevent fungal infection.

Third, grasp the suitable harvest time

In a certain range (from white to red period to full red), the lower the maturity, the more durable the storage. The experimental results show that the early red fruit (more than 25% coloring) is the most resistant to storage, so the storage of fresh jujube should be mainly red fruit.

4. Control the storage environment

The practice shows that the suitable storage environment conditions are as follows: the freezing point of ① jujube fruit is lower than that of general fruit, and the lower the temperature is, the better the storage effect is when it is higher than the freezing point of winter jujube. The freezing point temperature is different with different maturity, so the winter jujube with different maturity should be treated separately, generally, it is better to master 0 ℃ ~ 1 ℃. Under the condition of cold storage, the relative humidity suitable for winter jujube storage is 90%-95%. When ② is refrigerated, the oxygen content should be controlled at 3% to 6%. Winter jujube is a very sensitive variety to carbon dioxide, and the appropriate content of carbon dioxide should be 2%-4%.

5. Adopt reasonable storage equipment

On the one hand, jujube storage should have certain low-temperature airtight conditions to reduce water loss and respiratory intensity; on the other hand, it should maintain proper air permeability to prevent ethanol accumulation. Therefore, it is generally packed with 0.05mm thick PVC perforated bag during storage, which can not only prevent carbon dioxide poisoning, but also maintain humidity in the bag and ensure the fresh state of the fruit. When fresh jujube is stored at low temperature, it is generally packed in a plastic bag that can hold 0.5 kilogram (2 holes each with a diameter of 3 mm and 4 mm). 25% colored, injury-free, pest-free jujube fruit was soaked in 2% calcium chloride solution for 30 minutes and precooled for 1 to 2 days under the condition of 5 ℃ ~ 6 ℃. When the temperature of the jujube is reduced to 6 ℃ ~ 7 ℃, the bag is bagged and stored in a cold storage with a temperature of 0 ℃ ~ 1 ℃ and a relative temperature of 90% ~ 95%.

In addition, it is necessary to do a good job in storage management, including the adjustment of temperature, humidity and gas composition. At the same time, sample inspection is carried out every 7 to 10 days to deal with the jujube fruits that are no longer suitable for storage.