The jujube has a high nutritional value and is a “tonic king†in the fruit. The content of cyclic adenosine monophosphate in fresh dates is high, and it has the effects of enhancing myocardial contractility, expanding coronary blood vessels, inhibiting platelet aggregation and anti-tumor effects. At present, fresh dates have become one of the raw materials for screening anti-tumor drugs, but under normal conditions, only a few days after harvest are in a fresh state, and soon they will be spoiled and deteriorated. Most of the production is preserved with dried dates. For this reason, the preservation technology of fresh jujube is very important. First, the storage characteristics of jujube fruit Variety and tolerance of Tibetan-tolerance Fresh-date-resistance of Tibetan jujube due to its variety (most of its varieties are named after the names of places) differ greatly, generally the earlier varieties at the mature stage are not resistant to storage, and the late-maturing varieties have better tolerance for storage; The varieties of the type are not resistant to storage, while the small fruit varieties are more resistant to storage; the dry and fresh varieties are more resistant to storage than the single fresh food species; the anti-crack fruit varieties are more resistant to storage. According to further experiments, Xifengshan jujube and Xifengshan jujube in Hebei and Beijing are resistant to storage at a temperature of 0°C and a relative humidity of 90%. After 45 days of storage in small packages, the good fruit rate is as high as 79.4% to 98.7%. The species with the second highest tolerance are the North CheZhou jujube, the Changxindian crisp jujube and the gold silk jujube, etc. After 45 days of storage, the good fruit rate is 60.6% to 70.8%; the jujube and spot date are most resistant to storage, 45 There are few days left. Among the jujube strains in Shanxi, the Linqun group date and the jujube, the jujube date, and the Taigu gourd date had the best storage resistance, followed by the jujube, the fall date, the Tuntun jujube, the Langzao, the jujube, etc. difference. 2. Stored environmental conditions The freezing point of jujube fruit is lower than that of normal fruits. According to the test, the freezing point is mostly between -4.8°C and -5.9°C. Therefore, it is better to be -1°C to -2°C when refrigerated, and to 0 when the atmosphere is refrigerated. °C is appropriate. The jujube fruit is very easy to lose water, so the difference in vapor pressure between the fruit and its surrounding should be reduced as much as possible during storage. That is, the relative humidity in storage should be high, generally kept between 90% and 95%. Second, the pre-storage treatment of jujube fruit Ripening and harvesting maturity is one of the main factors affecting the storage of jujube fruit. The ripening of jujube can be divided into two stages. One is the brittle phase, that is, the stage before the fruit surface changes from green to white and coloring; the other is the mature stage, that is, the skin turns red and the fruit surface begins to shrink. In the mature stage, it can be divided into three cases: initial red (coloring below 25%), semi-red (coloring around 50%), and full red (coloring 100%). Jujube ripeness is low, and it is well-tolerated. Tests have proved that the jujube fruit used for storage should be selected from the early red fruits or harvested between the early red and the semi-red in the late stage of crisp ripening. 2. Pre-harvest measures In order to improve the storability of fresh jujube, the canopy and jujube fruit are sprayed with 0.2% calcium chloride solution or sprayed with 150-fold high fat film, 1000-fold thiophanate or percarbonate for 15 days before harvesting. Sodium can prevent fungal infections. 3. The storage of jujube for packaging processing ensures that the humidity is a major factor in ensuring the low temperature conditions. The use of perforated plastic bags can not only maintain proper air permeability, prevent ethanol accumulation, but also improve the humidity of the storage environment. Keep the fruit fresh. Generally 0.18 mm thick PVC film bag is used in production, and 8 holes are punched on both sides of the 15 cm and 22 cm bag. There are 16 holes in total. After 32 days, the 32-hole bag can be changed for storage. Causes anaerobic respiration to cause decay. Third, storage preservation technology Sand storage selection of storable varieties, harvested in the early red to semi-red, picking non-injury fruit, in a cool damp place, the bottom shop 3 cm thick wet sand, put a layer of fresh dates (a jujube thickness) , And then spread a layer of sand, and then put the second layer of jujube, continue to sand, put the third layer of jujube ... ... so piled to 30 cm high. In order to prevent the sand from drying, the surface can be sprayed with fresh water to supplement the humidity. This method can be stored for more than 1 month, jujube fresh and crisp, less nutrient loss. 2. Refrigerated selection of 25% to 50% of the color of fresh dates, placed in a plastic bag with a capacity of 1 kg, each side of the bag to play 3 to 4 mm diameter holes 3 to 4. The selected fruit is soaked in 2% calcium chloride solution for 30 minutes, pre-cooled at 7°C to 8°C for 1 to 2 days, then transferred to a cold storage at 01°C, and stored at a relative humidity of 60%. At that time, the relative humidity in the plastic bag remained above 90%. Check once after 3 days to 5 days, then check once every 7 days to 10 days. 3. Atmospheric storage of storage-resistant varieties of fruit, harvested at 25% coloration. At a temperature of 0°C, oxygen concentration of 15% and carbon dioxide 5%. Note that jujube fruit is sensitive to carbon dioxide and its concentration should not exceed 5%. 4. Bio-environmentally modified atmosphere storage This is a traditional storage method in China. According to ancient records, "take two stone tanks. Really river mud, well water. Spread mung bean on the top. With a bamboo urn inside the cylinder. Into the mud two inches. Place the fruit on the cover and seal the mud solid. Bean sprouts long date On the fruit, the taste is new.†This is due to the high respiration intensity of mung bean germination, which rapidly consumes the initial oxygen in the storage environment and increases the carbon dioxide content, which is a simple dynamic atmosphere storage. This method is worth our reference. In short, the preservation of jujube fruit, no matter which method is used, should follow the following steps. 1 Select late-maturing good varieties that are resistant to storage. 2 appropriate pre-processing. 3 spray or immerse the water quickly pre-cooled. 4 perforated plastic bags, layered in the library. 5 The temperature in the warehouse is controlled at 01°C, the relative humidity in the bag is 90% to 95%, and the carbon dioxide concentration is below 5%. 6 Inspect in time, find abnormalities, and deal with the change of storage fruit in time. China Agricultural Network Editor