Storage methods of jujube fruit

1. Timely harvest

Jujube fruit maturity is one of the important factors affecting fresh jujube storage. Many studies have shown that there is a negative correlation between fruit maturity and storage performance. The lower the maturity, the more storage-resistant the jujube fruit. The storage-resistant of white ripe fruit is better than that of early red fruit, and the storage-resistant of early red fruit is better than that of semi-red fruit. The storage performance of different harvest periods in 1985 in Institute of Fruit Tree of Shanxi Academy of Agricultural Sciences showed that the good fruit rate of semi-red fruit was over 90% and that of full-red fruit was only 43.87% after 90 days of cold storage at 0℃±1℃. Jujube fruit storage preservation, most varieties should be in the jujube fruit coloring about 50% of the half-red harvest is appropriate, early harvest, poor quality, late harvest, such as Lubei winter jujube, white ripening sugar has exceeded 20%, taste is very good, can be appropriately early harvest.

II. Storage conditions

Temperature is the most important factor affecting the storage effect of fresh jujube. In a certain range, the lower the temperature, the better the storage effect, but not lower than freezing point, otherwise it is easy to cause freezing damage. According to the determination, the freezing point of Langzao jujube at half-red stage is-2.4 ℃ ~ 3.8 ℃. Some varieties such as Linyi Lizao are easy to appear cold damage symptoms on the surface of jujube when stored at 0℃~-2℃ for a long time. During storage, we should pay attention to the observation of temperature. The storage temperature of most varieties of fresh jujube should be controlled between-0.5℃ and 1℃, so that the respiration of jujube fruit is in a very weak dormant state.

Moisture fresh jujube is a kind of fruit easy to lose water. According to the experiment, the water loss of jujube fruit is more than 5% after being harvested and stored in single layer at room temperature for 24 hours. The taste is stale. According to the test, under the condition of storage temperature 6~10℃ and relative humidity 70%~80%, the water loss rate of jujube, apple and hawthorn stored for 14 days is 22.2%, 1.2% and 11.2% respectively. It can be seen that the temperature has a great influence on the storage of fresh jujube. The results showed that the relative humidity of fresh jujube should be controlled between 90%~95%, and the moisture retention effect of 0.03~0.06mm non-toxic polyethylene perforated plastic bag was good.

Many studies showed that fresh jujube was sensitive to CO2, CO2 higher than 2% would accelerate fruit softening and browning. The suitable gas composition for storage of most varieties of fresh jujube is O2 3%~5%, CO2 less than 2%.

III. Storage methods

After harvest, put the dates into special fruit boxes. During transportation, remember to handle them gently and unload them gently to prevent collision damage. Before storage, jujube fruits should be selected, graded, cleaned, disinfected and precooled. The above procedures should be completed within one day. Then, the fruits should be packed into 0.01~0.02mm non-toxic polyethylene or polyvinyl chloride plastic film bags with a capacity of less than 5kg. The bag mouth should be tightened. Two holes with a diameter of 1cm should be made on both sides of the bag in order to facilitate ventilation and eliminate harmful gases. They should be placed on multi-layer storage racks. Attention should be paid to inspection during storage. The jujube can also be put into a special storage box lined with 0.02~0.03mm non-toxic polyethylene or polyvinyl chloride film, and the film bag mouth is covered and not sealed, and stacked for storage. In recent years, the special fresh-keeping bags for fresh jujube storage developed by the Institute of Agricultural Products Storage and Fresh-keeping of Shanxi Academy of Agricultural Sciences can remove harmful gases in time without punching. The capacity of each bag is about 10kg.

The above several storage methods, the warehouse before storage to disinfect, the temperature should be adjusted to the appropriate temperature. According to the present management system of our country, it is advisable to select 5~10t or 20t automatic cold storage or FACA flexible climate controlled storage developed and popularized by Shandong Province Fruit Research Institute for storage. It is more economical and practical to build a small storage with a storage capacity of 5t, with an investment of about 20 thousand yuan; a storage with a capacity of 20t, with an investment of about 40 thousand yuan. Ordinary farmers can bear it. If the operation is good, the cost of building the storage can be recovered or even saved after 2 years of storage. On the basis of small cold storage, gradually transition to small climate controlled storage. Small cold storage flexible mobility, warehousing and storage convenience, if the storage capacity is large, can also build small cold storage group or small climate control group.

IV. Prevention and control of storage diseases

Spraying 0.2% CaCl2 and 0.2%~0.3% KH_2PO_4 on trees during fruit growth period before harvest could improve storage tolerance and reduce incidence of physiological diseases. Treating jujube with TB2 after harvest can effectively kill pathogens and pathogenic microorganisms on jujube surface, reduce the incidence of fungal diseases and improve the storage quality of jujube.