Preparation of Chinese Cabbage before Storage
1. Harvest of Chinese cabbage
(1) When harvesting, choose the morning or evening with low temperature to avoid rainy and hot weather. In high temperature weather, Chinese cabbage has strong respiration and transpiration, which is not conducive to the preservation of nutrients in Chinese cabbage. Dew on the surface of cabbage in rainy days will induce cabbage to rot and deteriorate.
(2) The harvesting method of Chinese cabbage: Stop watering five days before harvesting, which can prevent Chinese cabbage from absorbing a lot of water and affecting the later storage. Select eight-ripe Chinese cabbage, cut it from the bottom with a harvesting knife (leave the root 1.5~3cm), and then gently put it into the box, paying attention to handle it with care. Avoid causing mechanical damage. Tips for universal refrigeration: the harvesting utensils and utensils for holding Chinese cabbage should be disinfected before use to avoid the infection of germs after harvesting Chinese cabbage.
2. Chinese cabbage grading
After harvesting Chinese cabbage, we should do a good job of grading. The purpose of classification is to improve the economic value of cold storage. The so-called "good cabbage is more worth storing".
First-class standard: the appearance is basically the same, the knot is tight, and the clothes are good; No old side, scorched edge, swelling and cracking, lateral bud germination and mechanical damage;
Secondary standard: similar appearance, not compact enough, and average finish; There may be slight mechanical damage.
Step 3 precool Chinese cabbage
Pre-cooling is an important guarantee for the fresh-keeping effect of refrigerated cabbage, which still performs respiration and transpiration after harvest. During this period, it will consume the nutrients and water stored in the growth period of Chinese cabbage. Pre-cooling can reduce the respiratory intensity of Chinese cabbage, inhibit its transpiration and reduce its physiological consumption. In addition, precooling can also help Chinese cabbage to better adapt to the low temperature environment of cold storage.
The pre-cooling methods can be natural cooling pre-cooling, water pre-cooling, cold storage fan pre-cooling, vacuum cooling, etc. If conditions permit, it is suggested to choose vacuum precooling, which is fast and effective. (Higher cost)
Cabbage cold storage management 1. Cold storage preservation parameters of cabbage
Cabbage cold storage can be installed with fresh-keeping warehouse or controlled atmosphere warehouse, and its fresh-keeping parameters are as follows:
① Cabbage stored in modified atmosphere.
Temperature: 0℃;
Relative humidity: 80% ~ 90%;
Gas composition: oxygen 2%~%, carbon dioxide concentration 8% ~10%;
② Cabbage fresh-keeping warehouse
Temperature: 0℃;
Relative humidity: 80% ~ 90%;
Storage time: 1 month
2. Temperature management of cabbage cold storage
During storage, the storage temperature should reach the predetermined storage temperature within 48 hours, and the fluctuation value should not exceed 65438 0℃.
When the temperature is too high, individual molds and germs will start to move, leading to the infection of Chinese cabbage in Yuzhong. At the same time, with the increase of temperature, its respiration will be enhanced and the physiological loss of Chinese cabbage will be accelerated. If the temperature is too low, it will freeze!
3. Humidity management of cabbage cold storage
The relative humidity of cabbage cold storage should be kept at 90% ~ 95%. If it is higher than this humidity, Chinese cabbage will rot easily. When the humidity is too low, Chinese cabbage is easy to lose weight, soften and shrink, and lose its edible value.
When the humidity is insufficient, the humidifier in the cold storage can be used to make up the humidity in the warehouse. In addition, hygrometers are placed in the front, middle and back of the warehouse. The hygrometer should be placed in a place not affected by condensed water and airflow vibration, and the accuracy of the instrument for measuring humidity should be 5%.
4. Gas composition management of cabbage cold storage
When Chinese cabbage is stored in a fresh-keeping warehouse, the warehouse body is relatively "sealed". After storage for a period of time, the concentration of carbon dioxide in the warehouse increases, producing other harmful gases.
Therefore, in order to create a suitable breathing environment for Chinese cabbage, it is suggested that the fresh-keeping warehouse of Chinese cabbage be ventilated and ventilated. At least once a week, when the temperature drops or at night.
Cabbage is stored in modified atmosphere, and the gas components in storage should be detected regularly by gas analyzer to prevent the gas components from being out of balance.
5. Other management matters
Precautions for stacking: Cabbage is generally stacked in 4 ~ 5 layers on the storage rack. It should not be piled too high, which is convenient for ventilation and reduces the temperature around the vegetable body. Let the cold air circulate completely in the warehouse;
During storage, Chinese cabbage should be sampled regularly to check whether there are diseases, chilling injury, discoloration, water loss, rot and other phenomena, and if there are any abnormalities, it should be removed in time. (applicable to fresh-keeping warehouse)
Cabbages shipped from the cold storage should be heated slowly to prevent onions from condensation and deterioration due to excessive temperature difference.
Matters needing attention in handling: handle with care, handle with care, and avoid mechanical injury.
In the process of transportation, cold chain transportation should be implemented for long-distance transportation, and normal temperature transportation can be selected for short-distance transportation.